Welcome!
Not really directly in answer to your questions but:
1) I have bought SIMs from Telestial and they have always been prompt and have no problems. Being able to call (in my time zone no less!) if problems/questions can be worth the extra expense.
2) The CBW rates to Lichtenstein (FL) are so good I can't beleive they'll last (but its been a year since I started using my Riiing SIM). I expect one day we'll wake up and the rates will be more inline with everybody else. So its good to have a backup plan when (if) that happens. For me having a UK number is worth not having to explain what country code 423 is and why I have a number there
Let us know what you end up doing.