Andrew wrote:

I use an old fire door that came out of Boots Brighton refurb
Being a fire door it takes my weight if I need to clean the
window and allows moveable storage arrangements underneath.

I used 40mmx3mx1m butcher block, it's supported on battens around four
walls, similarly it'll take my weight, the plastic drawer units left and
right underneath can be pulled out.

http://andyburns.uk/misc/desk.jpg