WWI workshop – what's going on here then?

A friend of mine posted this on another forum (not aviation), so I asked his permission to post it here to see what we can work out from it:

This was taken at Halton during WWI. On the left, posing with a block plane is Harry Fincher, (1885 – 1951) who enrolled into the RFC. Also in the picture are three German POWs manufacturing parts for aeroplanes.

So, anyone got anymore information on what is in the picture, Halton and the use of POWs in making bits for planes?

Harry Fincher:

Richard

MORE: the plane standing flat on it’s iron on the centre bench is giving me conniptions – is this sabotage???