Best windows for period houses

[SexNamesRFab]

We have a 1930s house with very pretty original timber windows. They will need replacing one day but as they are a pretty feature we've patched them up best we can for now.

We're planning to revamp the 1970s extension and would like windows to tie in. Have you had a good (or bad!) experience with trying to match original period windows?

We asked round for joiners who could do it. An estate agent gave us the name of a local firm who are good at windows. We've not got them out for a price yet, but I think its going to be a lot!

Friend paid £30K for all new windows in her 1920s home that matched the original. With encapsulated stained glass. They look fantastic.