What will their opinion on sap marks be? Bearing in mind they wont come out even with abrasive polish.

bubbles would not be caused by birds. Bird dropings make the paint look like it's been rubbed with very fine glass paper. Kinda dull. If you have had bird damage tho I would suggest getting diabondbright protection (or whatever its called now - ultrra guard or something) It's not cheap but its garanteed so they wouldnt beable to fob you off again.

The thing is, i pointed out another mark i have on my paintwork to the guy at the Vauxhall bodyshop, and he said it was caused by bird shit, and thats not covered under warranty. So surely he can just fob me off and tell me that the bubble on the bonnet, and the sap marks aren't covered too.

take it to vaux if its started bubbling already then this time next year the paint work might look a mess, you nothing to loss its under warrenty

Armor all heavy duty car wash (around £2.45) is good for that kind of thing.
As for paint, take it back to vauxhall it's covered under waranty.

As a few of you might know i've got a Corsa C which was brand new in March. Its Flame red.

I've recently noticed on the bonnet an area of paint about 1cm in diameter where it is bubbling up from underneath, and yesterday when i washed it i've noticed the whole car has sap in the paint which wont come out with regular tutle wax polish.

I was my car once or twice a week and polish it every 3 - 4 weeks so this is pissing me off.

Can anyone reccomend whether it would be worth my while taking it to Vauxhall, and if not what weak abrasive polish i should buy. My dad keeps telling me to get Zymol but i'm not spending that amount on polish.

Cheers guys