Very bad English. He bought it from the shop, not in it.
He could have bought a bathroom in the shop too, of course!
Fair point. But stating the obvious. See also "mae hi'n feichiog ac yn disgwyl babi".
I'm lost on how you can buy a bathroom in a shop. I would say, "I'm remodeling my bathroom." "I picked out tile for my new bathroom.". I'm lost with the meaning.
'ystafell ymolchi' can't be 'washroom'?