Expansion tank leak

[Buggy]

Hi,
just discovered a pin prick hole on the expansion tank. Is it ok to get welded or should I buy a new one?
Cheers,
Mark

[Buggy]

Thanks chaps.
Took another look at the tank and I don't think it will be long before other holes appear so a replacement it is.
Anyone got one for sale or should I contact the usual breakers?
Cheers.