| In answer to my own question, I fitted the one I had to the rear caliper, and
It's bl@@dy marvellous, bleeding the system through is an absolute breeze, and without any need to mess about with opening and closing the bleeder.
So good in fact, I've ordered some for the fronts. ( A massive £15 for Stainless Steel ones delivered)
If anyone knows what size the clutch bleeder is (it looks smaller) let me know, as I'll do that as well. | 
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