I'm not sure about driftwood but you can use grape vine? You have to sand off any sharp edges and you can pick it up from pretty much any reptile store.
As for dirt, Rodipet carries peat which hasn't got any chemicals in it and should be safe for hamsters
You can also make a good digging area with a lot of chinchilla sand!
https://www.rodipet.de/shop/einstreu...torf-25-l.html
EDIT: Forgot to mention, even though the site is in German you can order to the UK. We have the silver millet, moss and two little wood stands with water bottles for our hammies.