New vs. old mechanism:
After a good clean and re-grease of all moving parts of the mechanism, I carefully maneuvered everything back into place - which is a nightmare of a job.
I got carried away and did the final assembly.
I was well chuffed, until my eyes caught this:
I was so keen to get everything back together - I forgot to install the blower motor! So, the blower housing cover went off again (12 screws), blower motor in, 12 screws back in - and a quick test of wiper and blower revealed no issues!
Now I can finally install the new apron - the only reason I removed all this stuff!