Update, The tyre still had 20 PSI left in it, mileage since the puncture is around 200, initially the ultraseal quickly sealed the tyre, yesterdays run was brisk and heavily loaded, I looked at the puncure after 70 miles and all appeared well, upon the return journey the rear end felt soggy, this mornings investigation revealed a blob of ultraseal and evidence of ultraseal being flung around the underside of the mudguards, I re-inflated the tyre and the leak has stopped, I would have thought that this puncture would have been an ideal candidate for ultraseal, just a carpet tack, and not even all of the way in.
theres not a lot left on the tyre so I will keep an eye on it for the time being as deflation was slow and gave plenty of warning.
Stewart
Snake Oil
doesn't like the heat maybe??
is on trial with it in thier home delivery vans.