Should I use a vpn with my iptv service

It depends. If you live in the UK, Yes. If you live in a country which mandates a blocking of IPTV services, you should use a VPN. If you have an ISP which blocks IPTV services or restricts traffic, you should use a VPN. If none of those apply in the slightest then it's should be considered as optional.

which vpn service I should get

Whichever one you want. There are many services around. PIA. Torguard. NordVPN. Look into it and try find which one you prefer.

I use PIA out of my own personal preference.

you should not use routinely vpn unless you have issue with the connection

usually if you have trouble with connection like pausing / freezing /reloading its iptv provider issue

that's why we are all here we are looking for the best IPTV provider which difficult to find since every body say we are the best

I do use 1 occasionally. I get throttled by my isp sometimes, even though I pay for 1gig.

Depends if your provider as a vpn built in, if he as them some cases are u may experience buffer if u have vpn turned on while theres one running on there server, as they conflict with each other, ask provider 1st, but my personal preference is either nord or digibit, not used a vpn for a while, ours is inbuilt and all is fine

Any vpn will do the job, just use a dummy email and prepaid debit card, but remember, a vpn will significantly slow down the speed.