Interesting, of course I can only speak for my own experience here but as I understood it the relay controls both the signal that is sent to the starter and to the immobiliser and thus would dictate whether the signal is read correctly to allow starting ! As an intermittent fault and based on that idea I swapped out the starter relay for one of the others, in my case the horn, and the issue went away, car started each and every time, but as soon as I returned the original relay, back came the starting problem as described by Lord300 I just thought that rather than Lord300 keep buying expensive parts and spending large amounts of time and effort removing fitting them just give it a try and if it fixes it then fantastic if not its back to the drawing board? My problems began last summer and I wasted money on a new battery before I looked at the connections on the starter (earth) in case it was iffy, I knew it wasn't an alternator issue and as it worked 90% of the time with no problems I didn't think it was fuel or such like. I looked at the battery in the keys, they were fine so it seemed to me it just wasn't communicating with the car. What you get when you insert the key is everything lights up and you have full power so the auto headlights, radio, memory seats, mirrors etcetera all work perfectly but the car has nothing other than the solenoid click, turn the key off and back on again and most times it fires up and away you go ! Over time the issue gets worse and eventually the car just won't start. I'm awaiting some new relay units from the States, not going to get it through the MOT with no horn, but who knows when I'll get them, had never considered cracking them open and re soldering but it is worth a go, hell anything is, and if it's your second car or you can afford to have it off the road ! Lets face it, we all love these motors for the way they look and the interior size but they don't have the best build quality in the world. I may well give the solder idea a go and thanks for suggesting it.