I am using Oak windows for my barn conversion project. The linseed oil treatment I have used does not stand up to the weather too well. Does anyone know of a good treatment that will protect but not change the appearance of my expensive windows.

If you haven't already, you should do a search of the forums. Under search type in linseed oil as topic, and 'search all' and you'll find all kinds of info on the subject. I hope this helps. Good luck.

I get asked this question all the time - and have never found a good answer. Linseed as you have discovered, is very short lived outside.
A glazing contractor told me this morning that he has been using somthing (he couldnt recall what), on his oak glazing cover strips, that Ronseal had recomended - you could try them, - it stabilises the timber but still allows it to turn grey under/as a result of UV - this was the end in mind for him.

Most things look nasty, but Charltons Timber 01373 812 501 did have some sort of oil that they thought would work, you could try them.
Good luck and please post any possitive results on this page

I'm told than os colour who produce an excellent hardwax oil for timber floors now produce an exterior product. I have also used siekkens hls basecoat which stains the wood slightly - it's only just been applied -will keep you posted.