Cheers guys, went ahead this morning.
Mixed just over half a sachet with about 9 litres of water. Was pretty watery and dried within the hour. Hope it wasn't too diluted and the lining hardly slides when it comes to putting it up!! :oops:
I'm a trainee in p&d and use Leyland at college.
You're right, the undercoat is real thick and regardless of what the tin says, a spot of White Spirit does work. Although placing the tin in a bucket of hot water for 10/15 mins is preferred.
Benj