I wish you luck with this, I too, live in the Romford area and have been looking for quite a while. Might be easier to tell you who NOT to try!
I started off with Busybees, the girl who came had a quick dust & Hoover then spent the rest of the 2 hours I was paying her for rearranging my bottles in the bathroom and talking on her phone as my house was 'pretty immaculate' anyway she said.
Next I tried Gleamteam who were OK but tried to get away with as little as they could, didn't go into any nooks and crannies if you know what I mean, they could do behind the sofa or chairs as they were not insured!
Thought I would next try Mollymaid as they profess to be the best. Same again with them, only did what you could see, not very thourough, ended up with them sending just 1 lady (they started off with 2) who would finish in just over an hour and still charge me £50!
I'm still looking so if you find someone good let me know! Maybe I'm just too fussy but when im paying £50 for just over an hours work I expect them to be good!