If you search for web designer jobs in the UK on Indeed, most jobs are in the £25k to £30k range, with a slightly smaller selection between £30k and £35k.
London may be in a class of its own, but elsewhere in the UK £35k is considered decent money.
London may be in a class of its own, but elsewhere in the UK £35k is considered decent money.
That said, a "Web designer" role and a "Developer" role are two completely different things. £35k is about right for a decent web designer salary; but for a developer, that's more of junior to mid-level role, even outside of London.
Compare http://www.itjobswatch.co.uk/default.aspx?q=developer&l=&id=... and http://www.itjobswatch.co.uk/default.aspx?q=web+designer&l=&...