Sliding sash style upvc

[Oz07]

Are there any decent makes of sash windows in upvc with good u values? All that I've seen look too chunky. I would wonder how good the window performs with seals as well not having as much compression?

Edited 9 hours ago by Oz07

[Mr Punter]

I have used the "Rose" range in a couple of properties.  They are pretty good lookilikies for trad timber.