The 51st Shade of Grey?

This report of an albino squirrel in a Sussex garden caught my eye today, not least because we've had one visiting - or quite possibly resident in - our (Surrey) garden for several weeks now. Needless to say, it eludes all my efforts to get a picture of it, but it's there pretty much every day, often in company with an ordinarily grey squirrel. They seem to get on fairly well, at least as long as there's plenty for both of them to scavenge - which there usually is, what with all the bird feeders and the detritus falling from them.
 If the figure for albinism in squirrels - 1 in 100,000 - is correct, there are only around 25 albinos in the UK at any one time. In that case, they must all be living in Surrey - apart from the Sussex albino in the BBC report. I've seen them recently in two local parks, and this 2009 piece (also from the BBC News website) lists many other Surrey sightings. What it doesn't mention is that back in the Sixties there was a thriving colony of white squirrels in Beddington Park. There was some debate over whether they were true albinos - some had dark eyes - but they were so numerous as to be almost commonplace. That colony died out, but albino squirrels have never gone away - at least in Surrey. Is it something in the water?