You need to send both your passport (proof of identity) and BRP (proof of right to reside in the UK)
Yes, they get sent to the Swansea address
Yes, they get sent to the Swansea address
A passport by itself does not contain this information anymore (as of 2015 when BRPs replaced in-passport visa stickers), therefore you must also send your BRP with your identity document (passport).If you don’t have an EU or EEA passport, you’ll need to send in a visa that proves you have permission to live in the UK.