I should have pointed out that these are new homes. A dispute has arisen about some aspects of the work carried out by the electrical contractor. In this case, he would have been well aware that thermal insulation was to be installed and without him specifically requiring measures to prevent the insulation covering the type of fittings shown in the photo, he has clearly not demonstrated compliance with 7671. 
The problem is that I have to code the issue. Having carefully examined the install to ensure that the fittings are well clear of joists and understanding that the thermal insulation is effectively classed as non combustible, I am leaning towards the conclusion that the likely impact is one of lamp longevity rather than a potential ignition source. However, it’s late and I need to ruminate with a clearer head. 

lyledunn said:

I am leaning towards the conclusion that the likely impact is one of lamp longevity rather than a potential ignition source.

Could the lamps themselves not melt or catch fire?

If the issue is only lamp longevity, C3 (of sorts), but on the evidence so far, I find it difficult to see how an EIC could be issued.

In this case, he would have been well aware that thermal insulation was to be installed and without him specifically requiring measures to prevent the insulation covering the type of fittings shown in the photo, he has clearly not demonstrated compliance with 7671. 

I could see a good lawyer arguing that the installation complies when it was installed (pre-insulation) and if later other trades carry out work it's up to them to make sure they work in a way that doesn't leave the building less compliant than before they started. On larger projects of course I'd expect there to be come kind of oversight specifically to deal with the interfaces between different trades.

  - Andy.

In this case, he would have been well aware that thermal insulation was to be installed and without him specifically requiring measures to prevent the insulation covering the type of fittings shown in the photo, he has clearly not demonstrated compliance with 7671. 

I could see a good lawyer arguing that the installation complies when it was installed (pre-insulation) and if later other trades carry out work it's up to them to make sure they work in a way that doesn't leave the building less compliant than before they started. On larger projects of course I'd expect there to be come kind of oversight specifically to deal with the interfaces between different trades.

  - Andy.

AJJewsbury said:

I could see a good lawyer arguing that the installation complies when it was installed (pre-insulation)

And the other side would have argued that the electrician (or electrical designer) should have known that thermal insulation would be installed, or if he (or she) did not, he should have enquired whether it would be.

Had the builder not installed the thermal insulation, but a householder had done so later, it would be a different matter.

And since the thermal insulation contractor takes tea everyday in the same hut as the electrical contractor, you might imagine that he would have twigged!