Thanks for flagging this. I didn't want to post it myself as this is run in association with InsideFlyer UK, but it is a genuinely good deal - and currently the only TopCashback UK sign-up bonus available.

As the OP notes, there are various options on TopCashback UK even for non-UK residents, and you can be paid out through Paypal.

In terms of Avios.com, yes you technically need a UK address but suffice to say no-one is going to come round and knock on the door to check. You can of course transfer Avios from Avios.com to BA Executive Club (or Iberia Plus) using the "Combine My Avios" function.