In a short article to Deer in 2020, Chris Manning noted how Chinese water deer have been recorded in south Lincolnshire since 1976/77, when one was reported in the Lime Woods, east of Lincoln. There are also two undated records of animals on the boundaries with Norfolk and Cambridgeshire, and anecdotal reports of animals having been shot further north, between Grantham and Sleaford in the mid-1990s. According to Manning, only at Gibraltar Point near Skegness had a population been sustained, with regular records between 2004 and October 2014, including one animal being rescued from the promenade water feature in 2011 and returned to the Point's nature reserve. Two subsequent inland records, in 2012 and 2013, may have been deer from this population, but there were no confirmed sightings until early May 2020, when a mature buck was photographed for the first time at Alkborough Flats, just northwest of Scunthorpe at the confluence of the River Trent and Humber Estuary. It appears, from the current data, that Lincolnshire lacks a self-sustaining population. iRecord holds only two records from Lincolnshire: one for a deer hit by a car on dual carriageway near Scunthorpe in June 2018, and the other a mature buck found dead on the strandline on Skegness beach in February 2021.
In his 1992 review of water deer in Bedfordshire, Bernard Nau wrote that the Kings Lynn fens of Norfolk had a wild population “pre-1967”. According to the Norfolk and Norwich Naturalists' Society, however, the first recorded sighting of Chinese water deer in Norfolk were two individuals seen at Swim Coots and Ling's Mill in the east of the county in 1968 (I believe there is a typo in Lever's 2009 edition, in which the date given is 1958). Initially, these deer were considered to be muntjac until one was killed on the Staltham bypass later the same year. It was subsequently established that the animals, both bucks, had escaped from a private collection near Staltham and, in the Norfolk Mammal Report for that year, the authors comment that “there seems little chance of the species becoming established in the county”. On 14th August 1969 a deer was reported at Potter Heigham, and two bucks were killed on the A122, one near Outwell and the other at Nordelph, in September of the same year. In the 1969 Mammal Report, the authors muse:
“This is [a] singularly interesting find and suggests that the species might be wandering after all. We may perhaps see more in years to come.”
Two further reports came in 1970, one at Cley reedbeds during May, the animal being mobbed by lapwings, and the other from Terrington St Clements in October.In his round-up of the colonisation of Norfolk by water deer and muntjac, published in the 2019 Norfolk Bird & Mammal Report, Richard Moores notes that records of water deer began increasing in the county from the mid-1970s, particularly from the Broads. This increase continued through the 1980s and the population began expanding, particularly along the Yare River valley northwest from Reepham to Surlingham, during the 1990s. It was at the turn of the millennium that new populations were founded along the valley of the River Waveney, although many were apparently short lived as they were not reported in the 2010s, while the Broads' population continued to expand, particularly in the Hickling/Horsey area. Over the past decade or so, new populations have become established in the northwest of the county, around Thornham and Titchwell, while animals from the north Broads have spread into northeast Norfolk and significant increases have been noted in the Waveney Valley. They remain scarce in Breckland, owing, presumably, to the scarcity of suitable habitat.
We have little data from Suffolk, particularly on the spread of the species, although they don't appear to have arrived until at least the mid-1980s. Indeed, between January 1980 and December 1983, the Suffolk Natural History Society organised a survey to evaluate the distribution of deer in the east and west of the county and found no evidence of water deer. In his summary of the survey's results, published in the Society's Transactions journal in 1984, Stephen Cham noted:
“In Cambridgeshire there are good numbers at Woodwalton Fen NNR only 38km from the Suffolk border and it is quite conceivable that Chinese Water deer could come from this direction. They also occur in the Norfolk Broads and there have been unconfirmed rumours of sightings at Oulton Broad near the Suffolk border.”
The first confirmed record for Suffolk appears to be an adult buck that was killed on Wangford Road, north-east Suffolk, close to the Norfolk and Cambridge boundaries, in mid-January 1987. Subsequently, the first record of a live animal is from the west of the country. Mid-morning on 7th May 1989 Rob Macklin spotted a buck in Potbriggs Wood at Minsmere Nature Reserve. Macklin was warden of the reserve at the time and, writing in the Transactions of the Suffolk Natural History Society in 1990, described how he initially considered the small deer browsing along the woodland ride to have been a muntjac until he got within about 80 metres (87 yards) and was afforded a better view through his binoculars. A second sighting, also of a buck, was recorded by Macklin in June of the same year, this time on the north side of the Scotts Hall Coverts on the reserve. Shortly after Macklin's first sighting, an escapee animal from Kilverstone Wildlife Park was reported at Shadwell Carr.
Several more reliable reports were received during the 1990s from Suffolk and, based on the most recent (2016) survey data published by the British Deer Society (BDS), the species is currently widespread through northern and eastern parts of the county, but either absent or very patchy to the south of the A143 and west of the A140.
The southern extent of water deer in Essex seems to be around Harwich, after both sexes were recorded on the Hamford Water reserve in September 2014 - the first video evidence was captured on a trailcam set on the reserve during spring of 2015. Recent anecdotal records from the Stour Valley at Scotland Street and Stutton, however, suggest a possible route of travel into Essex from Suffolk, although exactly how they arrived on Hamford Water unobserved is still not known.