Gentlemen,
I would not drill any holes in my pump either, but this is after the fact. The chap who did drill said holes is a semi-retired older Dutch gentlemen who, apparently, seriously knows his pumps and even bought some of the Bosch factory testing eqpt when they were getting shot of the old way of doing things 'way back when...'
Anyway, I now have a pump with more holes in it that before it went to get a service, although they're on the inside. Not much I think I can do about it other than hook it up and see how it runs. I certainly don't have the expertise to be able to say 'what utter madness' to the gentlemen who did it, much as in my head when I heard what he'd done I was screaming something altogether more colourful.
Incidentally, I've used Joe's excellent linkage tour to check that and it's spot on. I'll see how the pump runs.
I'll also go to try and find the NGK plugs and see if they do any better.
Many thanks for your advice. I'll report back on the pump, which is clean and has lots of little red paint blotches dotted about it. Perhaps it caught measeles whilst on its trip.
JH