Wow! Thank you!
They certainly appear the same... I'll whip mine off in a while and measure it. They are a bit crude in all honesty, so perhaps the measurements aren't that crucial....we shall see!
Again, beyond the call of duty!
Thank you!
Edit : Told you they were bloody silly little things! Just got the existing one off, and gave it a quick measure...I suppose it could be a tad squashed through use, but it looks circa 30mm tall, and about the same at its fattest point. Hole at the base is about 15mm diameter..