Advice/recommendations re sash windows please

[Lewestwood]

Hello

We have a couple of sash windows that need mending, but are also considering having the whole lot replaced with double glazed sash windows.

Can anybody who has had work done to their windows give me an idea of cost (per window) for mending an existing sash, replacing like for like, wooden double glazed sashes and also the upvc option as well, if anybody has had that done.

Also recommendations for companies to do this.

Thanks very much

Lianne