Do window frames need to be the same colour?

[wateryfalls]

I'm having a window quandary.

We live in an old house that's had a new extension at the back.

The extension has off white window frames, I don't know the exact colour.
Some of the house has stone mullion with original metal frames, some of the Windows have been replaced with timber frames, the dormers in the roof were put in by the company that made the exertion Windows.
The new front of house frames have been painted French Grey and blend in well with the existing metal frames. Should we paint the back ones too, baring in mind the extension & roof ones will remain white.
DH thinks yes, I'm not sure. I love the coloured ones but then we'll have a mix of different styles and colours.
Sorry for such a boring question but any opinions would be welcome.

As you've already got a mix of windows, I'd be inclined to leave them as they are. Unless you replace all of them (and any associated brickwork), you won't end up with identical windows anyway.

I recall a UK television series (can't remember the name), where mention was made that in some cases the planning department (or whatever) like the differences to be visible, as part of the history of the house.

Many older houses have gone through changes, as various owners make their own decisions. Often, that makes the house more interesting.

Thanks. I think I agree with you.