I've got hold of an in line booster to try & improve the radio in my 56 plate Fabia.

The instructions that came with it refer to joining the blue wire to pin 5 on the lower wiring block which is described as being blue or blue\white in colour.

However in that position the wire on my block is blue\black. (see pic).

Does anyone know what wire I should be attaching the blue cable from the in line booster to?

Yeah the blue black is fine, just basically wants connecting to a live.

I doubt if it'll work though - The Fabia already has a built-in booster in the aerial base so chances are there is not enough signal getting to the headunit end to be boosted (usually because the boost circuitry in the aerial base is corroded and had-it). I've had the same in our Fabia and tried, as you are doing, with both signal boosters and a friends Fabia headunit.

The solution was a new aerial and base from a dealer for a few quid and half an hours work to fit it.

Thanks folks, I'll try the booster & be prepared to swop out the aerial abd base if the reception doesn't improve.