Success or failure in replacing uPVC hinges and gearing - original obsolete

[cliverlong]

This is a "did you succeed" rather than a "how to" question. I have 25 year old uPVC windows with Roto (?) tilt swivel hinges /gearing etc. The mechanism is unobtainable and one supplier has suggested a complete replacement system . Even with labour, this would be much cheaper than a complete replacement unit. Even if I take measurements carefully, there is a risk the new mechanism won't fit. I'm asking for feedback on anyone who has attempted this change and whether you succeeded or failed.

Thanks

 

[crank39]

If it's a Roto mechanism I guess it's a tilt n turn window, I know it's a DIY site but to be honest I'd leave it to a professional like a window doctor type outfit, too many variables in mechanisms to mention and even I don't like doing them so to identify one that will fit, order it, wait 5 days, strip the old one off, fit the new one after trimming the lengths down to suit, setting it up, finding out you ordered a wrong part but you can't send it back because you've cut it, getting the window to work arghhh, nightmare