There is some good general info about EU sims HERE
We have 3 as our main sim at home but it only allows 12gb abroad.(no daily charge as our contract was in July 2022)But that will change next year. Now with various campsite wi fi that 12gb might be enough.
Very positive reviews of the Tiekom deal but they charge €15 to send sims to UK. But you can park the sim unused for €3 month.
So the front runner for me is the Popit deal.Not seen any reviews as yet so a bit new and untested.I expect good/reasonable reception if it uses the EE network. Also it can be started in UK and then presumably allow UK TV streaming. I presume you can just cancel when not needed and then get a new sim.But their customer service is good so they might respond to the "parking option"
I would be interested if anyone has used the Popit or seen any reviews about it.