I've been away all week, but I'm pleased to report there's been a steady stream of sightings at White Lion Meadow car park, and I went down last night and saw, straight away, an absolutely huge vole. It's getting difficult to spot anything now, though, as the vegetation's so lush (second photo down). So if a vole like the one in photo 3 stays quite still, you may miss it completely!
I include this beautiful picture of a surprised baby water vole, taken by my friend on the Wild About Britain forums. What a smashing shot - puts all mine to shame.