Well that was a total waste of time. I try to avoid buying everything online but no choice.
I'm with @opps - forget B&Q. Better to go and find yourself a timber yard or decent builder's merchant for stuff like this or go on-line. Filler really needs to be a 2-pack and have some flexibility - even P40 (car body filler) is better than any of the one-part fillers. I've had the EWS stabiliser from Reddiseals (specialist sash window repair components firm) in the past - they always have it in stock. They also sell Metolux 2-pack filler with mixer nozzles which always deliver the correct mix ratio (ideally requires a heavy-duty caulking gun such as an Cox or Ox brand)
An alternative supplier is Chemfix, who also have rot repair videos on their site (follow the link)
TBH it doesn't surprise me that B&Q and Wickes don't carry this stuff - only three of the timber merchants I deal with within 10 miles actually stock it - bit of a specialist product
That's the biggest problem, or at least if it is puttied in, years old and must be re-used. Secialist glaziers I've worked with used a "putty router" (basically a modified back-handle router - like a Festool OF1010e). I have tried this with an old router, but it wrecks the cutters, doesn't do the router a lot of good and throws sharp carp in your face - so maybe not worthwhile for a one offThe only bit I'm really worries about is removing the glass.
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