Not too far from Datchett - Maidenhead Folk Club is every Thursday at
The Ferry , Cookham. Right by Cookham Bridge, straight up the side of the river from Maidenhead Bridge.

Windsor has a few things of a loosely Folk bent at Windsor Arts Center
with the Soundhole on Sunday and an acoustic do on Wednesday.

The Rose and Crown - London end of Slough High Street is a Folk Friendly pub with occasional Saturday sessions

The Herschell Arms Herschell Street Slough is a Rabid Hotbed of Irish Traditional music, especially on a Monday night.

Also on Monday and not too far down stream.Staines Folk and Blues Club is in the Three Tuns and is a nice small club

Tuesday will usually find me at the Crown and Treaty in Uxbridge, and
that is Denham/Slough end of the High Street near the canal.

That should keep you going for a bit, and of course London is NOT that far away with all the clubs and sessions there.