Your link at 1310 goes to an American web design company, Bramley!
Questions about mobile phone service providers come up often here. There are only four actual networks in the UK. (Vodafone, O2, EE and Three). All other networks are simply 'piggyback' services, that make use of the transmitters and infrastructure of those four. So, for example, if your problem with EE is poor coverage in your area, there's no point in considering in using Virgin Mobile because they use EE's masts and the coverage you'll get will be exactly the same.
My own preference is to use Asda Mobile, that I'm perfectly happy with. They use the Vodafone network and, unlike some other cheap services, they've got UK call centres who usually pick up their phones within seconds. (Some other services only have web-based support, where you end up going round in circles when trying to get a valid response from a 'chatbot'). People who only use the internet to check their emails, read the news headlines and post on AnswerBank (rather than watching countless YouTube videos or constantly playing online video games) only need to pay £5 a month for 3GB of data, with unlimited calls and texts to UK numbers thrown in. Moderately heavy users of the internet can get that data allowance upped to 10GB by paying just £7 per month. (Those prices are for 4G services. 5G deals start from £10 per month). As with all PAYG 'bundle' deals, from any provider, there's no contract, meaning that you can change the deal (or leave altogether) at any time. See here:
https://mobile.asda.com/bundles
(Click 'View all bundles').
Asda Mobile has got plenty of fans among ABers, with GiffGaff (which uses the O2 network) also being very popular here.
https://mobile.asda.com/bundles
[NB: GiffGaff doesn't have any 'proper' customer support though. You have to post any queries on the community forum].