Dirk,
Good man re engine number, and I have to agree with you re the 'risk'. I'm doing my best to do a meticulous rebuild of exactly how my Nova was "way back when".
The garage I use for MOT's does only that ... MOT's (ie no repairs) so I'm confident that I'll get a fair assessment from them.
It would be bad enough to be involved in a 'damage only' accident like the one you had, but if life and limb was concerned .... I'd want an independent recognised authority's documented assessment. Mind you, the MOT issuers always stress that the condition of the vehicle they assess only relates to the date and time of the test, so in the event of an insurance claim I suspect that the issuer of the MOT would probably use this 'get out clause'!
Alistair