I really wouldn't bother trying to find a decent S/H one as you would be hard pressed to find a really decent one that age and as previously stated, the new one which costs only £200 will fit without problems.
"I put a TD5 on my 1984 110. No probs. Just had to make 2 small bulkhead blanking plates. Either side of the fuse box."
If they are the two holes I am thinking of I had them as well and a genuine part rubber-gromet is available & very cheap (about £1).