Been out of the UK, moving back. Got my own phone but not sure which network gives best coverage and minutes/text/data?

Anything else like streaming services offered as part of packages I should aware of?

I use Three and have done for 6 faultless years. The only downer was when they stopped the (truly) unlimited data tariff.
My works Vodafone loses coverage where the Three soldiers on.

Three didn’t work for me in Worcestershire, Wiltshire and Gloucestershire further than 1 mile from any town centre. Terminated contract early due awful signal.
Giffgaff now.

Vodafone because I’ve got no coverage from any network at home but Vodafone would sell me a femtocell (SureSignal) and none of the others would.

Just get a payg SIM and try it out. Networks vary from area to area. Giff gaff for O2 or 321 on 3 are pretty cheap to try out. No tie in so if it doesn’t work then bin it and try another one.

Another Three fan. You need to check their coverage in your typical usage areas but I get “free” 4G and unlimited data, texts, calls. All sim only for £18 (its more pricey now I believe)

Voda probably sell cells because their infrastructure is the worst out of the lot of them.

Three has been the best option for me I live in remote town so signal on all the networks is poor but the Three wifi app works really well at home, I can make and receive calls perfectly.
I have 4gb of data, unlimited texts and calls for £9pm, I only have Sim deals as i buy my own phones cheaper elsewhere.