Noting that some have assumed this is a rented property, though I don't see that stated. It does make a significant difference ...
The electrician couldn't find the problem, insisted on conducting a full EICR.
Did you agree to that before he did it ?
... not that there is any compulsion to comply with BS7671 for an old installation. Sounds like a complete scam to me, or am I missing something?
Well if this is a rented property, then that is a "tricky" one. Technically that is correct, there is no law that says an installation must be retroactively made to comply with the latest regs. But there are other issues that can come into play :
The first of these is a legal one. A landlord has a duty of care to the tenant (and any visitors) to provide a "safe" property. Non-compliance with current regs doesn't make an installation unsafe - but it can do and this is where the coding on an EICR matters, and it would seem, why the OP is unhappy as some of the codings.
The second one is that, as hinted at, tenants may decide to use any non-compliances to their advantage. I've perhaps been lucky in that I've only ever had one tenant with that mindset. As it is, both my properties have EICRs with no defects against the current regs - being fairly modern with no faults, achieved by upgrading the CUs to fully RCBO. IMO that has to be one of the simplest defences against a charge of letting an unsafe property - being able to hold up a piece of paper that says it was safe according to an "expert" should cut off most attempts at scamming the landlord fairly quickly.
I think we are not being given the whole story, the lack of pictures and detail of exactly what circuit caused the 'short' the electrician maybe 'at it' likewise the installation maybe a death trap we just don't know.
I rather agree. Why the reticence to post pictures (or give a reason why they aren't available) ? It
could be as simple as he never thought to take any at the time and would need the tenant's permission to go back into the property to get some.
A scan of the test results sheet shouldn't take much effort though.
But so many unanswered questions :
What was the circuit ? If it was an RFC then any competent sparky should be able to narrow down a dead short fairly quickly. It shouldn't be much harder on a radial to get down to a specific cable segment.
As to the low IR - could it be that it was a whole installation test and there was something still connected ?