Re: Unfair contracts
In the UK you get an offer, it's followed by a formal contract, and you aren't committed to accepting the job until you sign that; you start after they've received your signed contract and signed it themselves.
So don't resign your existing role until you've seen the contract and are happy to sign it.
Do read it, and do challenge clauses you're not happy with. I've declined a clause in a bog standard employment contract with a multinational blue-chip on the grounds it constrained and infringed on my IP rights to existing and new non-work related creative works; the HR department went, "Yeah, we didn't mean that" and we reached rapid agreement.