Gearing Clutch Repair JCB Drill

I have a JCB CD20Li 20V Cordless Drill

I had stripped it to check the inner workings, all laid out in exact positions for reassembly.

Then my less than helpful Brother slipped against the table and mixed all the parts.

I thought I had them back in place but on re-assembly It now does not change speed etc.

I really need to locate an exploded diagram of the workings (gears & clutch) so I can re-assemble in the correct positions.

I contacted JCB in Ireland by phone and was promised the diagram by return, but of course it never turned up.

I imagine they don't want you to do a repair that they can charge a small fortune for.

any help will be much appreciated.