Hi Edward and welcome to the forum,
Regarding tax id, this will depend on the supplier. It's far more common for a wholesaler to require a tax id than a dropshipper, however more and more dropshippers are now requesting a tax id as well. If you do find that one does require it, using a UK tax should be fine.
Regarding payment, if you are going to accept PayPal, and most customers will expect you to, then you will most likely have some issues if your account is new. PayPal may well put a hold on your account, usually lasts up to 28 days, and all the funds will be locked during the hold period. What you can do is contact PayPal ahead of time, give them the details of the suppliers you will be using and that may make it easier to get through the initial new account stage with them.