Hi Steamy, Caught a few on Malarky over the last couple of seasons. One of my m8s has had plenty of 30s up to low 40s on it so its a thumbs up from us
If you are prepared to drive to Kent, then I know a guy who sells it for about £4/kilo if you buy over 30 kilos.
Send me a PM and Ill give you the number if interested.
I purchased a 1 man STI about 2 years ago and its still going strong. If the groundsheet does not fit then maybe there is something wrong with the bivvy, groundsheet or both. Take it back if your not happy...