Pacu all gone
Yep that's about it, the metal frames just added another seal which wouldn't have been needed if the windows had gone all the way to floor, and sealing to metal seems to have been the problematic bit.
Black sealant is:
GOLD LABEL
POND
AQUARIUM
SEALER
the web address on the tube is
www.huttonaquaticproducts.co.uk
It's very good stuff, i'd use it over silicone anyday. Sticks everything with a waterproof seal, non toxic and can set underwater so is fish safe, and none of the nice strong smells that silicone gives off either.