Just seen this on the RMT website. Can't find consultation details anywhere yet; but I remember when LM proposed similar changes they were posted on their website.
http://www.rmt.org.uk/news/rmt-to-fight-ticket-office-carnage/
http://www.rmt.org.uk/news/rmt-to-fight-ticket-office-carnage/
PROPOSED TICKET OFFICE CLOSURE FROM JUNE 2016
GSM London Bridge
Queens Road
Peckham
Selhust
Tulse Hill
Wandsworth Common
West Norwood
Streatham
Streatham Hill
Streatham Common
Gipsy Hill
GSM Victoria
Battersea Park
GSM East Croydon & Purley
Carshalton Beeches
South Croydon
GSM TL North
Cricklewood
GSM TL South
Loughborough Junction
Tooting
Denmark Hill
Great Northern
Alexandra Palace
Enfield Chase
New Barnet
Palmers Green
STATIONS WITH MAJOR CHANGES WITH PEAK HOURS OPENING ONLY
GSM East Croydon and Purley
Dorking
Leatherhead
Epsom
Ashtead
GSM Brighton
Burgess Hill
Hassocks
Merstham
Horley
GSM East Coastway
Eastbourne
Bexhill
Lewes
Polegate
Oxted
East Grinstead
GSM West Coastway
Chichester
Angmering
Worthing
Crawley
Littlehampton
Horsham
Portslade
Bognor Regis
Barnham
Hove
Chichester
GSM TL North
Leagrave
Flitwick
Harpenden
GSM GN North
Sandy
Hitchin
Kings Lynn
Huntingdon
Stevenage
St Neots
Letchworth
Royston
GSM GN South
Potters Bar
Hatfield
Welwyn Garden City
Hertford
STATIONS IN PHASE TWO NO TICKET OFFICE IN FUTURE but DATE NOT KNOWN YET FOR CLOSURE
GSM London Bridge
Norbury
Thornton Heath
Balham
GSM East Croydon and Purley
Caterham
Wallington
Carshalton
Purley
Sutton
Caterham
GSM Brighton
Coulsdon South
Reigate
GSM East Coastway
Sanderstead
Falmer
GSM West Coastway
Shoreham-By-Sea
Lancing
GSM TL North
Mill Hill Broadway
Radlett
Elstree
Luton Airport Parkway
GSM TL South
City Thameslink
West Hampstead
Great Northern
Hornsey
Gordon Hill
Winchmore Hill