Michael,
Then you have a 214 engine, not exactly sure when it was introduced but around mid-50's, they did evolve over the years, last used in TK and TJ up in to early 80's. The QL had a 28hp engine bud with deep end in sump with strainer on oil pump, it would not be necessary to use that engine in a CMP because the front axle is further forward than a QL, giving adequate clearance. You hear stories that the army converted CMP to Bedford engines, but I am certain this was not a general case, because the British disposed of their CMP vehicles early on, having more than enough British made vehicles and spares to be going on with. These mods would have been done in civvy street, undoubtably.
I have not fitted a 214 to a CMP, but have done it to a Bedford MW. The 214 used, was a army rebuild, for a TK, the clutch housing had to be changed over in order to get the rear engine mountings to fit, then it was found the flywheel was smaller, and starter different. Other than that the rest of the engine was the same. To answer your question on the clutch, you will have to remove it or take the pan off and post a pic of the clutch. The drive plate can be relined by a motor factor or matched up for a replacement.
Richard