Added to the common faults sticky also thanks all +++

That's great, Sean and Neil +++ Im sure it'll help others do some preventive maintenance as the trouble with this fault is that you dont know its a problem until, one day, you need to use it.

Pretty sure that’s my problem too so I’ll have a look now it’s getting warmer. One question, would I be right to assume that each tumbler is different and has to be replaced from whence it came in order to allow the key to work? I know that’s how it is with house locks, so it seems a reasonable extrapolation.

Yes exactly, which is also how you can re-key a replacement mechanism to fit a different key, although in that case it does help to have a box full of recycled tumblers.

Well, I took it to bits, but it wouldn’t come out through the little door for the rear lights as it had been put in from the other side of the mounting bracket, so the rear light cluster had to come out along with the boot lid liner.

The tumblers were, indeed, all seized, although not as bad as Vera’s, so I took it all apart and cleaned it.

But then, on reassembly, I got some of the tumblers mixed up, so had a painstaking fiddle about to get them in the right order to fit the key!

And, to add insult to injury, one of the tiny tumbler springs disappeared into another dimension! No amount of searching could find it, so my lock barrel is now missing one tumbler. I confess, however, that I don’t think the compromised security on the boot lock will really be an issue.

It’ll all go back on the car tomorrow, unless some kind soul could express post me a teeny tumbler spring (but why would you have a spare one of those?).

Well, if someone happened to have a box full of disassembled locks and teeny tiny tumbler spring for exactly this scenario, it would be rude not to share wouldn't it +++

Mine was properly seized and I couldnt get the assembly apart so its been sent on a journey to the D2 doctor ..... +++

If you really are happy to let me have a spring, please name your price - cash or chocolates?

It could very well be that the battery is faulty, but any modern smart charger requires a certain amount of electrical resistance and voltage feedback to initiate a charge.
Which in English means that smart chargers won't charge a totally flat battery.

(The work around is to couple a good battery in parallel to fool the charger)

Yes, you're right. I connected my C-TEK charger and that had the same result. However, this battery was well and truly dead and nothing revived it. I did get a replacement from the supplier though - eventually!