Fleeting

The situation in question does not have a vague answer, placing out of reach is not acceptable and anyone undertaking an EICR should be...

Agreed it has no relevance.

Not an unreasonable point, but BS7671 (rightly or wrongly) makes specific provision for those lamp holders.

What difference does above 5m make?

You can't suggest out of reach as a means of protection in this instance. If you are undertaking EICRs you should be well aware of this.

The way they have cut those holes I'm not sure I would want them doing any work in my house.

Stupid question time, but are you SURE it is a gas boiler not electric? Replacing a gas boiler with an electric one would easily...

Try and establish which circuit or circuits are causing it by switching off the mcbs one at a time to narrow it down.

Picture 3 looks like your night tariff consumer unit. The supply for this almost certainly comes from picture 6 and is controlled for...

How are you planning on connecting the conduit into them?

No.

Assuming this is T&E the cable would require protection from solar damage and possible mechanical damage. Does the circuit have 30ma RCD...

Make a Rudolf 😀

How are Shell involved? What do Garo say?

That is a poor attempt at electrifying. That cable should have restraint where it enters to prevent undue stress on the lamp...