quite abit of over plating
In my opinion the bit that's been cut out where the prop shat comes out was done to raise the shaft, maybe for a bigger propeller but has been carried out in an un-sympathetic way. If so it would be one of the later Northwich sterns if they remain bulkhead brackets would give an idea if it was a 9 or 15 fitted but the water inlet has gone at least from the outside. However if overplated it may be possible to see it from inside as Ling has 2 one blanked for pup and a second for the big engine. Though as said before it does not suggest which boat it is and as there were a few cut in half.