1. there should be a button called family and friends, this is where you can add other memberships 2. i'm pretty sure the credit card has to match your address on your details, as for collection are you living out of the UK? I'm not sure how it works in regards to international members I think you pick them up from the box office. 3. You cannot pick your exact seat, you can pick the area you want to sit in for example lower or upper and if memory serves me correct you can pick a certain area but it's not very specific.