[Arran]

You get what you pay for, there may be a way of making a switch model power supply work, without severe hash, but Aliexpress is not where you will find one, though you may find a 240 v mains dropping transformer on there, or fleabay, cannot vouch for quality. If would look to one of the larger online parts dealer, Digikey, Newark, or Mouser, all three sell an assortment of transformers, as well as any other parts you need, you could also try Edcore, or A.E.S. Personally I would build a linear power supply with salvaged transformers, you can take two 120 volt transformers and connect the primaries in series, do you have isolation transformers for razor outlets? David Tipton, on Y.T has a parts supplier he uses, maybe join a vintage radio club and find out where they get parts?
Regards
Arran