If you are in the Apple ecosystem then a refurbed 8 is a very good step up if you are back on an old SE or a 6 for instance. If you do not use the super cameras of the newer machines then really there is nothing against an 8 and you can get operating system updates for a quite a while more. For £199 - I would go for it.
My daughter is 22, on her first graduate job in London and had just bought a new Iphone 12 Mini. She raves about the 5g, but she lives close to Central London. She has 'returned' her old student used 7 Plus to me (I bought it for her second hand about 2 years ago) .
I have an Iphone 6 as a company phone - so no longer supported. Although I have used it as personal phone always (company is fine with that) it is getting frustrating being so old, and the GPS is faulty. I bought a £6 a month Sim card in the 7 Plus, stuck it onto the same Apple ID and suddenly I have two phones that seem to transfer most things interchangeably. I can now download the NHS contact tracing app too. And for once my personal emails are seperated out. All good!
Yes the 7 plus has a weak battery but it will spend its life on wifi or a car holder and I am not a social media fiend.