[T Creighton]

Hi Tony,
My original ones were two piece which was just as well as the bottom bit was long gone.
I would suggest the base would be best out of treated ply.
Inside is 4 3/4"x1 3/4"
Wall Thickness is about 1 1/8"
Depth is 1 3/4"
Base is probably 1/2" max
Cheers, Terry