Nearest builders merchants I can find is chandlersbs.co.uk/
I know its a bit of a way but DPD in oldbury were advertising for afternoon drivers on local collections,
Could try pallet work like DPD do afternoon collections,or if you haven’t already ring an agency (I know I know) tell them what your after see where they say to go and apply direct if you like it.
Hope this helps will post more when I’m home