Thats something I've not come across on the 75/ZT, but I'm pretty sure someone will be along in a minute to help you out.

 

If you can get hold of a Haynes manual, it has some good pictures and a detailed procedure for replacing the barrel. It does look quite fiddly, though. Getting the barrel out needs some lock-picking skills.

It looks as if the immobiliser coil isn't part of the assembly - it just pushes on over the barrel and connects with a plug, so even if there's one with the new barrel, and it did need programming, I don't see why you couldn't keep the old one.

 

Thanks for the info guys. Doesn't sound too bad. I tried to buy an electronic copy of the manula on Flea-bay but nothing arrived!! Hey ho it's off to Halfords we go

 

I had the same trouble about two months ago, parked up,went into shop for a dipped headlight bulb,came back, and the key would not go in at all, after about ten minutes of fiddling about (I was getting close to the brown trouser stage I can tell you) the key just goes in as easy as wink, dont know what it was, no trouble before and no trouble since, I could understand if the lock had been playing up before but no, nothing, and its fine now (touch wood)
I did squirt a bit of WD 40 in just in case.

 

rather than wd, graphite is the go. even rubbing a lead pencil across the keyhole will fix it.