bonnet catch problems

I put the bonnet on for the first time after welding the series 3 "hinge" bracket onto my series 2 bulkhead: that end of the bonnet worked fine.

However, i was (rightly) nervous about the bonnet catch end at the front. Having put the bonnet down softly onto the mechanism, it didn't want to release the bonnet (although the handle moved back and forth OK).
I was able to eventually loosen the catch mechanism from underneath and after wiggling both the mechanism and the bonnet, i managed to get them apart.

So, what is going wrong?
The spike doesn't appear to be 100% straight, but i also wonder if my catch mechanism is working correctly.
Is there a common issue with these?

Straighten up the pin, leave the catch unit bolts a tad loose for first try.

I've got one to refit this weekend, a fiendishly cunning device that will stubbornly refuse to release the bonnet until you get it spot on.
Be persistent, it will stop fighting you eventually