Do Thai house use a ring main or is every light connected separately from the fuse board.

No ring finals in Thailand.

Lighting and outlets are wired as radials, up to 10 or so double outlets daisy-chained on a 20A breaker wired in 2.5mm².

Lighting in 1.5mm² on a 10A breaker.

Older homes may have lights and outlets on the same breaker.

I have just changed the ceiling rose and it only has 2 wires. It looks like the circuit is looped from switch to switch, as apposed to the UK where the ceiling roses are are connected.

Sound about right? It is an old apartment-circa 1970-80.

In Thailand, the locals like to feed the switch, which is indeed why you only have 2 wires at the light.

It's actually common practice now in the UK.

There are a few methods that can be used, depends on type of property and cable used.