Replacement BMC 1.8 flywheel casing/PRM150

[Slim]

Has anyone else had difficulty mating a PRM 150 to a currently available Calcutts flywheel casing using all Calcutts supplied parts?

Component parts are:- Ali flywheel casing incorperating rear mountings, flywheel casing adapter plate (approx 18" dia in 12 mm plate) sorry about mixed units? Ali gearbox adapter plate for PRM 150. All the parts dry fit together with a little fettling.

Firsst attempt.  Bolt flywheel casing to engine and fit rear flexible mounts. Fine. Bolt flywheel casing adapter plate to casting. Fine. Bolt gearbox adapter plate to gearbox. Fine . Lower gearbox on chain block and tackle , offer up g'box to engine, align input shaft to driveplate splines and mate g'box with engine. Fine. Now the problems start. Bolting the 'box adapter plate to the flywheel adapter plate is impossible Just can't get 4 of the 6 bolts in even when cutting them down to the minimum length.

Second attempt. Remove flywheel adapter plate and assemble out of situ. Still can't do it as there's not enough clearance between between the gearbox casing and the adapter plate to allow for the head of the bolt even leaving out the supplied spring washer ( intended to use thread seal) . I'm not prepared to leave out the flat washer. 

Third attempt. Remove g/box adapter plate from box, bolt it to flywheel adapter plate then bolt both plates to g/box. Can only get 4 of the 6 bolts in. The other 2 boltholes are masked by the 12mm thick plate. 

Fourth attempt. Make 2 cutouts in the 12 mm plate to allow the hidden holes to be accessed. 

This was where I got to today when it started raining. I'm doing all this on the boat, in a marina, 75 miles from home and a reasonably well equipped workshop. 

I'm reasonably sure I can get it together tomorrow if it doesn't rain.

My main reason for posting is to ask "what have I done wrong?". I was going to go to Calcutts to ask but fell asleep in front of the fire. 

Sorry, no photos and lousey spelling . Doing this on a tablet

I know I'll get it done but it's a b#$%&@d of a job.