Crows foot socket, like this https://www.amazon.co.uk/US-PRO-Crowfoot-Crowsfeet-Spanner/dp/B079H3JC9G/ref=sr_1_5 (although for the engine mounts you only need a 15mm one). That allows you to get under the manifold and heatshield and undo the top nuts.

For the two top bellhousing bolts, if you remove the upper intake plenum and ignition coils, you can get at them from above with the ring end of a combination spanner.

OK, sounds like a Plan.
Will report.

Finally made it. Was a real fight with the bolts and myself and the car.....had to have a serious word with Rangie, if it refuses to give me the bellhousing bolts I would have to make it see its creator....that seemed to work :-)
I can see the parts of the flex plate now and can change it.
While I am there I wanted to check the output shaft seal, but am I right to assume that if the "flywheel" and ringgear is clean and dry that I do not need to change it? The engine is very oily but the inside of the bellhousing is clean...

If there's no oil on the inside of the flywheel (the part closest to the engine), then the rear seal is fine. Sump and oil cooler hoses are the usual leak places on a GEMS.

Whew, finally made it.
Flex plate was in 10 pieces, got it out and the new one in, now the whole procedure in reverse...
Thanks for the help, still more things to fix....

Putting stuff back together is always easier than taking it apart. You aren't dealing with seized bolts and sitting there working out how something comes apart, you just bolt it all together in the opposite order to how it came apart.

Yeah, that's true...!