Unfortunaley where lever locks are concerned they will tend to be expensive and come with a load of hardware a hobby picker doesnt want,
Lever locks to look for would be the easier ones to pick such as the older invincibles and profits which you should still find in some less busy shops, things like the chubb 3u115 is a good lock as are the union 2134's but again older locks that are not the latest BS specs so you may struggle in the middle of london,
I am gogin to go out on a ledge here and assume you are after pin locks,
In that case B&Q (its a big DIY store) will have the Yales etc that you would find commonly and at probably the best price at retail in the middle of london,
As for euro cylinders etc you will have to go to locksmiths for anything that isnt the cheapest and crapest of the lot (diy stores tend to stock the cheap crap as thats what diy'ers want
) things like Mul-T=Lock will be authorised official dealers as will other simular brands,
Maybe someone with a shop that frequents here could drop you a address and number for you to call in to otherwise as the others have said i think your better off on fleabay,
How long you stopping? would you have a postal address?
)
