Doc, kindly stop insulting me. I am asking advice, I know full well how a wiring circuit works and am only asking for your opinion. If you can't offer it without insulting me don't offer an opinion at all.
I can assure you there are no insults intended in my previous post. The observations are all based around the information you have given in your posts, with your own words. If you know how a circuit works why did you say in post #1 "
I've tried lots of combinations with both but neither work."? And as you say you are asking for an opinion. My opinion is that a competent person would fix your problem in 10 minutes maximum (per fitting), as lighting circuits are very basic electrical control wiring. You gave a link to an inappropriate tester that you said you had purchased costing £179.94 including VAT (from the link you gave). I honestly cannot believe that any electrician would charge over £100 to just reconnect your lamps for you. As such my advice was the most economical and practical solution to your problem is to get a local competent person to visit to rectify you fault.
A person who knows how a lighting circuit works would have simply identified the supply cable, switch cable, (feed to any second light worked off the same switch if applicable), and the outgoing loop to the next light in the circuit (unless its end of circuit). After identifying each cable it is just a simple matter of connecting Supply to switch, Switch to load, Load back to supply. Mentioning things such as the amperage of the circuit has no relevance whatsoever to identifying the correct connections at a light fitting. You logic sounds confused, and your understanding of how circuits work, and you method of trying random combinations, (as you mentioned in post#1), sounds potentially dangerous to me. Electricity can kill a healthy adult in less than half a second, anyone with the slightest understanding would not be "Trying lots of combinations" and switching the power back on to see if they work.
Some people may not like the truth when they ask a question and may try to imply they are being insulted. But the basics of how electrical circuits work hasn't changed and you are the one who has posted the details about how much, or how little, you understand about circuits, test equipment and how to prove something is safe and compliant with BS7671. Without insult I still think the safest and cheapest solution to your problem is to get someone in. Just randomly trying wires can also result in welding switch contacts, (or burning them out), so the switch doesn't work. e.g. random connections could end up with the switch being wired as a direct short circuit across the supply. this method is NOT recommended and is a very dangerous and an incompetent method in my opinion.
If you do not like my advice or opinion, that is something you are perfectly entitled to do. But please do not suggest I am insulting you when making observation based around the facts you have given. The content of your posts do not suggest anyone who understands fundamental electrical principles.
Doc H.