Thanks Roo and Annabel
I have sent enquiries to those two, as well as a few others I have found in previous posts.
I will post an update once I have got some answers and had the job done.

Hi
These people are in Balham near Halfords.

I've heard great things and if you use them please do let us know do we can keep the recommendation up-to-date!

Thanks for using NVN!

http://www.curtainworkshop.co.uk/about_us.php

Hi there, have you found someone? I am looking for someone who could cut my (ready-made) curtains to the right length and fit them with blackout lining.
If you or someone else have got any recommendation, please could you share?
many thanks

We are getting our loft habitable and I need to find someone who can make curtains for the Juliet balcony. It is a tricky window as there is very little space above the window on which to hang a curtain rail. Does anyone have any recommendations for a good, reasonable curtain maker locally? Our budget isn't very big sadly.

Many thanks