Standard SIM. All providers should now allow it under Ofcom rules.
Don't be fooled by data allowances though. With some providers unlimited everything can be cheaper than a medium allowance.
Edit: Make sure the router is not locked to a provider.
Connections: OnePlus 8 Pro, 4G+ (LTE) max 165Mbps down, 24Mbps up on Three Mobile, and B311 4G+ router, tbb tests normally 35-45Mpbs down, 65Mbps off-peak, 9-24 up.
Edited by pluralist (Wed 28-Jul-21 12:29:57)