Hmmmm, I might of wished I hadn't thought about this. I went into a branch of Maidenhead Aquatics and looked at the tanks and aquariums made by Seashell Aquariums. Whilst I'm not sure about the actual tanks, we quite liked the cabinets. They are made in solid oak not laminate, which fits in with the rest of our furniture in our house, and the wife has decided that's the style to go for.
Unfortunately, the tanks and cabinets in the range are only available as 16" deep, not quite deep enough for me. Seashell don't supply direct to the public, so there's no point trying to go down the bespoke avenue.
Does anybody know of a manufacturer of solid oak cabinets, specifically for aquariums? Aquariums Ltd and ND Aquatics only make laminate cabinets.