Sound editing

I have shot and edited a 20 minute short film. I also had all the sound redone and I had ADR done. Most of the sound does seem to be fine but there are a few area's where it sounds a bit sterile and that needs correcting. I would also like to enhance the ambient sounds in area's. The ambient sound which I feel is missing is the sound of London.
So it is only in certain area' s where work is required.
I would prefer someone in the London area as I could come and discuss and bring the project. We are having a premiere screening in dublin in 2 weeks so I would like to have it completed as soon as.
Thanks
Tom