It’s Colchester 1150 2 it’s a 2 birth I don’t no much about it, is it a big job to do taking the rail of n re doing it, sounds like I’ve defo bought one ready to scrap 🤦🏽♀️😑
It can be done, and can be very time consuming to do it right.
Best if there are two of you to keep the rail from bending/twisting when taking it off, As a quick guide:
Take out the centre beading/trim
Remove the screws
take the rail off, it may be well stuck in places
Clean off all the old mastic from both caravan and rail with blunt tool. wet wipes, then white spirit, finally clean with methylated spirit, this is the time consuming bit!!
use new mastic, I used sikaflex 512( others are available) on the rail and place back on the van, use new stainless steel screws, drilling new pilot holes, dont use the old holes unless you obtain thicker screws. Clean off all excess mastic and replace the bead.
you can buy new bead/trim to go back in.
good luck.