Well i went n got it fixed day before yesterday, �35 for a new tube, a plug in the hole in the tyre and all the labour. Went out a wee run yesterday n it seems fine.
The green tyre sealant (SLIME) will only work on very small punctures, the bottles say somethin rediculous like 12mm (we have them in the cycle section in halfords) but in reality the hole would have to be much smaller. If it leaks out into the tyre it shouldnt be too bad to get off, when someone brings their bike in to get a new tube fitted n the old ones a slime tube we usually burst it open n try n cover each other in the slime n once it dries itll usually peel off pretty easy (maybe half the reason it dont work to good!)