In the UK a lot of that is solved by using the NI number that everyone has to have to work, claim benefits, get a state pension, or pay tax.

For people who are employed it could be done by existing systems already used to calculate tax (which is deducted automatically by employers here so the systems to do calculations exist).

Self-employed people already have to register with HMRC.

For the rest it is a far, far simpler than the requirements of the benefits system and less prone to fraud.

> You cannot make UBI work from money saved by removing means testing.

No one claims it can be made to work using ONLY money saved from means testing. Something like removing means tested benefits together with lowering tax thresholds could work though.