The thread pitch is m7x1 mate. Can't tell you the length though I'm afraid but I'd guestimate they're about 12-15mm long.
A bit of silicone at the gearbox and cambelt end would be fine. It's for where the main caps/front cover join the block. Other than that the oe gasket should be up to the job.
Think they're closer to 25mm long.
These would do.
http://www.ebay.co.uk/itm/M5-M6-M7-...rial_Nails_Fixing_MJ&var=&hash=item3f2ba01608
cheers mate, sump arrived the other day much better condition than the one i have on at the moment... i do have some m7 25mm that i bought not so long ago so i'll give them a try.