MK Commando Switch Disconnector would provide a good fixed solution.
Couple of inches deep on a wall, bottom cable gland exit possible,
lockable in off position, IP54 16A are cheap, easy wire(*).


(*) By "easy wire" I mean their terminals are round-hole brass like a
13A plug, rather than Rotary Disconnectors which use an inverted V
cable clamp which has mandatory min cable size (otherwise the clamp is
tight but your cable is loose re fire).