I'm already decided to move to London , But i don't know if the recruiter i'm working with is not good, Or the average PHP dev salary is low.

There isn't much of a vibe if you can't afford to go out.

In zones 1-2 (or 3) that'll probably have to be a houseshare - but you'd still easily get a nice private room for that. The takehome of £45k is £2,797.27 /month after tax[0]. Even if you spend 50% of that on rent (inadvisable but common in London), that's still £1400 a month to play with. Which is still more than the total takehome of someone earning the London living wage[1].

I mean, you'll have to have a commute if you want a private, 1 bed flat or larger and you're working in Zone 1, but that's not exactly much of a hardship. My point is that with even the most basic level of sane budgeting, £45k is easily enough to live/work pretty much anywhere in London.

[0] http://www.thesalarycalculator.co.uk/salary.php [1] http://www.livingwage.org.uk/what-living-wage

That being said, whilst London has a nice vibe, if you don't know people here it can be isolating. Been here a few months and not really found "my people" yet.

If you can get 40k in Manchester then yes 50-55k should be achievable or contracting for more but that will make it harder to buy or set up a rental agreement if you don't have guaranteed income?

I'm seeing numbers from $50,000 - $60,000 for developer salaries in London. Obviously a lot of things come into play, but that should give you some idea:

http://www.itjobswatch.co.uk/jobs/london/programmer.do

and

https://www.glassdoor.com/Salaries/london-programmer-salary-...

Recruiting firms in general do not have your best interest at heart...but that doesn't mean you can't get a mutually beneficial agreement down.

There is also always room for negotiation.