What benefits are these then ? This is what we need, a truthful list of benefits and a truthful lists of benefits being outside of EU control..........
IMO, some benefits are, in no particular order;
Cross continent protection of workers rights, with recourse to a supreme court if flouted.
EU wide tackling of climate change. (Not that arsed about that me, but thats another thread)
Access to the single market. Nissan, for just one, chose to set up in Sunderland because of that.
(Probably) a better negotiating position re trade deals. Your point on us being the 5 th largest, I do have consideration for mind.
Free movement. Yeah, not perfect, but London is what, the 7th largest "French" city, and the growth of the part of London in terms of the skills and stuff they have bought over are great. Dead easy to move to Spain as well!
Reasonably peaceful these last few decades.
Cons? Again, no particular order.
The Euro.
The political elite and sheer waste of cash.
Free movement. Like I said, it does have drawbacks.
Meddling in pretty unimportant stuff.
Red tape.
It is a gravy train, no doubt. (Google MEPs pensions ffs!)
Costs a few bob.
So on balance, for me, the pros are tangible and worthwhile, mainly. But the cons are more irritating than plain bad.