Thanks for that advice - I did note from one of the chat sites that Ryobi and Mac primer bulbs are generally interchangeable.
I also noticed from the general trimmer site quite a few similar problems of cracked bulbs and general replies that these were commonly available from most mower repair places.
So, I cast the net a bit wider and found a repair place near my work who had the part. Like the others near home, he was still not all that complimentary about Ryobi stuff - but I got a positive result which was what I was really looking for.
Really found the site to be A1 in terms of useful advice.
Cheers
