Having had battery problems, I bit the bullet and bought a new one, unfortunately when I tried to replace it today, I found that the bolt on the negative terminal is stuck solid 
It has a Phillips head cross in the top, so I tried using that, but it started to sheer, so I decided to see if it would unbolt instead, however I've tried a 10mm socket which is too big and a 9mm which is too small.
I also tried a 3/8" and 11/32" neither of which worked either, so I have *no* idea what the shop that replaced the old battery put on it (and they've now gone out of business!) and I really don't want to try pliers or molegrips as may round off entirely.
I've soaked it as best I can with what was left of a small can of WD-40 and I'm going to leave it overnight in the hope that it will loosen up, but if I'm going to get this new battery on it, I need some ideas in case that doesn't fix it.
Out of interest, the bolt on the positive terminal is ok and I've loosened it a bit, plus I've managed to remove the bolts holding the ABS relay etc and the clamp that holds the battery in place, so I'm thinking that if I can remove the positive lead (and then insulate it with eg a plastic bag and gaffer tape) I may be able to get the battery out of its holder to work on it a bit more easily.
The other issue is that there's connections for the heated gloves and the Sat Nav on there, so I can't simply rip things off.
As a last resort I may have to try to drill the bolt out, but I really don't want to do that unless really necessary, so I'd be obliged for any useful suggestions.
It has a Phillips head cross in the top, so I tried using that, but it started to sheer, so I decided to see if it would unbolt instead, however I've tried a 10mm socket which is too big and a 9mm which is too small.
I also tried a 3/8" and 11/32" neither of which worked either, so I have *no* idea what the shop that replaced the old battery put on it (and they've now gone out of business!) and I really don't want to try pliers or molegrips as may round off entirely.
I've soaked it as best I can with what was left of a small can of WD-40 and I'm going to leave it overnight in the hope that it will loosen up, but if I'm going to get this new battery on it, I need some ideas in case that doesn't fix it.
Out of interest, the bolt on the positive terminal is ok and I've loosened it a bit, plus I've managed to remove the bolts holding the ABS relay etc and the clamp that holds the battery in place, so I'm thinking that if I can remove the positive lead (and then insulate it with eg a plastic bag and gaffer tape) I may be able to get the battery out of its holder to work on it a bit more easily.
The other issue is that there's connections for the heated gloves and the Sat Nav on there, so I can't simply rip things off.
As a last resort I may have to try to drill the bolt out, but I really don't want to do that unless really necessary, so I'd be obliged for any useful suggestions.