Currently have the following:
RWG Mobile PAYG. 5p call and text. 1p meg data.
Must make 1 call every 90 days to keep SIM active. Got tbh and say the reception isn't the best in my area. Support and top-up done through online chat/email, so get a fictitious email account! Easy to disable adult filter with a email request.
They often gave a 2-for-1 promo where you top-up £5-10 and get double, lasting ages.
Cheapest PAYG considering it only cost £5 to run the SIM, keeping to 90 day rule.
O2 Classic 321. (3p call, 2p txt, 1p meg data). Buy SIM eBay 99p. *They will stop selling these Sims soon, but the 321 pack will continue for customers, unless they change t&c.
IMO, the best reception out of all the mobile providers. Top-up with shop bought voucher for anonymity.
Now I'm told you need to top-up once every 180 days to keep SIM active (£20 year), and you keep all the credit, so if you're an infrequent user, you can accumulate a lot create over time
*There are O2 forum chat post that suggest you only need make 1 call every 180 days to keep SIM active, rather than top-up.
To turn off adult filter, you need give debit card for check.
Dropping the following;
1p mobile. They changed T&C. Must spend £10 every 60 days. If you don't spend £10, they will extract the difference from your credit balance. Essentially, you need top up every 2 months, makin it £60 a year to run.
Reception not the best either.