OK here are all the answers:
And well done to all those who got some towns correct
Ad Pontes Staines
Alaunodunum Maidenhead
Anderitum Pevensey (East Sussex)
Aquae Sulis Bath
Aquae Arnemetiae Buxton
Belgic oppidum Braintree
Blestium Monmouth
Burrium Usk
Camulodunum Colchester
Cataractonium Catterick
Clausentum Bitterne
Coccium Wigan
Colonia Colchester (again)
Corinium Dobunnorum Cirencester
Danum Doncaster
Derventio Brigantum Stamford Bridge or Malton
Dubris Dover
Durnovaria Dorchester
Durobrovis Rochester
Durocornovium Swindon
Durolipons Cambridge
Durovernum Cantiacorum Canterbury
Eboracum York
Glevum Colonia Gloucester
Hortonium Halifax
Leodis Leeds
Lindinis Ilchester
Londinium London
Luguvalium Carlisle
Magnus Portus Bosham
Noviomagus Reginorum Chichester
Olicana Ilkley
Pons Aeliu Newcastle
Ratae Corieltauvorum Leicester
Sorbiodonum Salisbury
Vectis Isle of Wight
Venta Belgarum Winchester
Verulamium St Albans