Guardian Prize-Help

[lashley]

19d applies oneself(exchanging knight for pawn for for theme word ?) 5,2 ??R?S/?? turns on?

11d from within a container mostly trash 2,5 ??I?T??

bahrain's facing regular losses 7

not a noisy fiesta apparently 7

thanks

 

[Toorak]

Works on

Ab intra

arisaig

ashford

[Toorak]

Parsing 

1 Worksop (theme word) - change p to n

2 a bin tra(sh)

3 alternate letters in clue

4 a sh (not noisy) Ford

[lashley]

many thanks

[MissSpell]

Thank you for the WORKSOP/N solution.

 

I'm still unclear as to the Theme?? I have all the place names, Loch and River, but don't really get what the theme is???