Thanks for all the replies.
maybe you have a faulty boot light switch so the car doesn't know the boot has been opened??
I'd thought of this but the boot light goes on/off along with the boot-open indicator on the dash.
There is a switch in the glove box on mine that in the off position disables the boot.So when you open the car with the fob the boot is still locked.To open it you need to press the boot button on the fob.
There's a key-operated switch on the drivers' floor of mine which I think does the same.
Ok, so judging by all you guys' kind replies, it looks like it's a saloon thing - at least it's not just mine!
I've thought of a few solutions...
1 - (and the most obvious LOL) - Keep the keys out of the boot when I close it. - This may seem easy but, hey, I've locked myself out once already!
2 - Carry the spare key. - This isn't practical for me as the spare key is a remote-type fob so it's too big to add to my house-keys bunch, which I like to carry in my trouser pocket.
3 - Buy a new key blade (only the blade part) from Ebay, get it cut to fit the car, enlarge the pre-drilled hole at the top if necessary, and add this non obtrusive key to my house-keys bunch. Due to it's lack of width I won't have much leverage when turning the key but I'd like to think I could borrow a set of pliers or something if necessary. I also think the alarm will sound when the car is opened but at least it'll open.
What do you all think?