Eventually, after changing the battery again, and trying every possible combination of clicks etc found in various online forums I made an appointment at a Renault agent. Prior to the appointment, I tried the remote every day without success.
The appointment was for today and we duly set off to a small Aberdeenshire village called Memsie (population 157ish), the city of Aberdeen (population 230,000 ish) being too small for a main agent!!
We arrived early and sat in the waiting area with a nice cup of coffee until the mechanic came in. He took the key so that he could move the car into the workshop for connecting to the diagnostic equipment, pressed the remote and the bloody thing worked. I couldn't believe my eyes.
I told him to go ahead and hook the car up and check the receiver and any other fault codes. He returned soon, saying there were absolutely no codes logged, which was unusual, but not impossible as the car has only done 5000 miles.
So we had a round trip of 65 miles, a charge of £58 for the computer, for bugger all!
We did learn however, that the car had no faults logged, and that the remote key fob does not need to be ordered from Renault, as they are a stock item, requiring only a session on the diagnostics to mate them to the car. I also learned that the remote never loses it's memory no matter how long the battery is out for, unlike many remotes, where the battery has to be changed within a certain time.
The downside is, the new remote key and diagnostic session costs around £180!!!
We also noticed that the remote central locking now engages when the car reaches 5 mph, which it has NEVER done before. SWIMBO bought the car when it was just a few months old and with a few hundred miles on the clock.
The car is out of the garage for about two days a month for a 2 mile trip to Tesco and had a new platinum battery fitted at MOT a month ago. I'm wondering if it needed a run to re-mate(is that a word) the remote, but I'm as at a loss as to why it suddenly started working as the mechanic was.