In reply to Andy Johnson:
I had an old (25 year+) Terra Nova hyperspace tent where the groundsheet had delaminated and become leaky - sent it back to Terra Nova who looked at it and gave me an option to replace it (at a cost) which I agreed to - got it back and have used it a few times since, including at the weekend there where the was a sustained torrential downpour - tent preformed admirably, and groundsheet was great, stayed dry!
Yup, it wasn't the cheapest to get renewed but Terra Nova did a great job on mine, would recommend them to repair their tents!
(I have no affiliation with Terra Nova, just a punter who got their tent fixed by them)
Good luck with getting your tent repaired.