The Sun Always Shines on Tytherley

(did you see what I did there?) One of the locals from the rookery on the hill on this lovely sunny frosty morning. Meanwhile we have solved the bath conundrum (how to get a bath that's big enough to submerge yourself in but still fits into the bathroom and doesn't cost a packet) and are now moving on to rainwater goods. It seems you can have plastic, steel, GRP, copper, cast, extruded or pressed aluminium, cast iron or zinc gutters. Copper and cast iron look lovely and cost a packet; plastic is cheap but I think our architect would hang himself if he thought we were going to specify that - any great thoughts out there? And rainwater harvesting - anyone done any calculations of how much you need to store for garden irrigation and carwashing purposes (we won't be using much on the latter, that's for sure....)