Update from the original page at
https://www.railadvent.co.uk/2020/03/coronavirus-the-full-list-of-railways-affected-by-covid-19.html, which is being actively updated - extracting data for "Coffee Shop territory" and near neighbours. Every report in our area shows some curtailment; one or two places elsewhere in the country are reporting "service as normal"; it's fair to guess that attractions in our area not listed are probably also curtailed - just not made the RailAdvent report page.
Blaenavon’s Heritage Railway (Pontypool & Blaenavon Railway)
Train services until 3rd May 2020 – CANCELLED
Chinnor and Princes Risborough Railway
Diesel Gala – POSTPONED
Date TBC – possibly October
Dartmouth Steam Railway
18th March 2020 – NO TRAINS
19th March 2020 – trains as timetabled
20th March 2020 – CLOSED UNTIL FURTHER NOTICE
Dean Forest Railway
CLOSED until end of April
Didcot Railway Centre
CLOSED until 4th April 2020
Gloucestershire Warwickshire Railway
Cotswold Festival of Steam 23rd – 25th May 2020 – CANCELLED
Visitors cancelled, possible home fleet event (TBC)
Further announcements to be made regarding pre-booked tickets
Timetabled trains on 21st and 22nd March 2020 – CANCELLED
More information regarding future events and timetabled trains TBC
War Time In The Cotswolds 25/26th April 2020 – CANCELLED
No confirmation of any revised dates
Gwili Steam Railway
Temporary closure until mid-April
Swindon & Cricklade Railway
SUSPENDED until May
Severn Valley Railway
Trains SUSPENDED UNTIL APRIL
South Devon Railway
SUSPENDED until 16th May 2020
West Somerset Railway
Spring Steam Gala – CANCELLED
Gala to return in 2021
Beer festival at Diesel Gala – CANCELLED
No confirmation of whether diesel gala will go ahead