Photographing Marsh Tits near London (1 Viewer)

I have only ever seen a couple of Marsh Tits and those views were far too brief. Does anyone know of any feeding stations in the home counties with reliable sightings of Marsh Tits? I would like to photograph them and I have tried a few RSPB visitor centre feeding stations before but with no luck. Any suggestions for good places to get close to this species? I have a car so can go anywhere surrounding London. Thanks for any help. Charlie.

Some of the sites that seem to have had Marsh Tits in recent years that have been photographed and added to the Birdguides Iris Gallery are Oxon: Otmoor RSPB; Northants: Earl Barton GP's; Cambs: Paxton Pits NR; Bucks: Linford NR.