At risk of a bit of thread drift, but hopefully the Mods will be tolerant, there is an excellent book about FIDO: Flying Through Fire, by Geoffrey Williams, from which I have cribbed this list of UK FIDO equipped airfields:
Blackbushe
Bradwell Bay
Carnaby
Downham Market
Fiskerton
Foulsham
Graveley
Ludford Magna
Manston
Melbourne
Metheringham
St Eval
Sturgate
Tuddenham
Woodbridge
Hope this is of interest.