heated up plastic pipe seems to be the fave, then you can mould it to exactly what you want
but of course that would be the DIY way, which i know isnt your thing
so just phone glyn i guess is the answer
What you should have said, Matt, is:
Send me the specs of what you need, and I'll make you a bespoke tool for the guttering you need to clean.
The price will be: ...£xxx.xxp
Then get the heat gun on a piece of guttering that costs £1.50 and sell it on at a massive mark up!
That's what all the suppliers are doing.. And I think they'd be daft not to!