I have a USA king size mattress, and its dimensions are 203.2 cm L x 193.04 cm W (80 inches x 76 inches). I'm not convinced that the Super King frames in the UK will be large enough for it, as Super King mattresses seem to be smaller in both dimensions. As such, I am attempting to build a frame for it myself.
I would like to adapt this plan to my mattress size, and using UK timber sizes:
I was able to find most of the required timber on Wickes, but some of the wider boards I need are on the order of 1 inches x 10 inches (25.4 mm x 254 mm, not accounting for actual board thickness), and I can't seem to find boards that are wide enough.
So my question is this: what is a good timber source for a bed project like this? I'd prefer something that can be delivered, if possible. I'm in Edinburgh.