Anyone have any hints tips for sliding the engine back onto the gearbox. Have done several reinstalls but for the life of me I can't get the 2.1 onto the five speed box. It is either 20mm to go sliding ti on or the top is on but the bottom is around 10mm out. I have not had so much trouble doing this before on my own but even with help I can't get it on. Assuming I have missed something or am doing something wrong.
TIA

Check the clutch plate alignment.

Make sure it is in gear.

You may need to back off the clutch cable

Put a spanner on the engine pulley and rock the crank backwards and forwards as you are pushing the engine in. The input shaft splines sometimes have issues syncing up with the clutch disk.

Remove your flywheel lock!!

Flywheel fouling