Do you still get the bonus points when doing Global Transfer? What other evidence did they request?
I'll probably ditch it after I've used the first pair of 100 quid credits (in and out of UK) and the bonus points are through as I read UK Amex gives pro rata refunds.
Yes, bonus still applies as you’ve not had a UK Amex within the previous whatever months - their bonuses are - any of them if you haven’t had any. Once you’ve had any Amex in the previous 18(I think) months, you’re only eligible for Plat Charge and BAPP (but you remain eligible for both) unless you’ve had any MR earning card (in which case Plat is out) or BA earning card (in which case BAPP is out). So, an ideal strategy might be Marriott->BAPP/Plat->Plat/BAPP. Once you’ve had BAPP or Plat bonuses, you only are eligible for the bonus on the other of those two, all others are then waiting for you to have held no Amex for 18m. Hope that makes sense!
As for requesting stuff, other than FR (which I’ve been through twice now), they’ve never requested anything. For FR I provided my Aussie bank statements from ANZ, they’ve never requested just wanted proof I was earning what I claimed to be, but I’ve never been asked for that when applying for any UK card.
And yes, pro rata refunds are still a thing on UK Amex, they’ve been threatening to remove them for ages now, but it still hasn’t come into effect (though I think that have now updated the T&Cs to reflect it - before it was part of the contract, now it’s goodwill, basically).
My most recent Plat was an upgrade from their Amex Rewards CC (when they offered 100k to do so), so that account is >10y old, but I’ve opened and closed countless UK Amex cards in that time, most recently BAPP in ~May, when they offered 50k Avios. The companion voucher has potential value too (I used to use the Lloyds bank upgrade vouchers, which let you originate ex-UK, and now I believe the Amex vouchers do too (they never used to), so even if not from SYD, a flight from Japan, HK or SG might be possible in terms of decent value).