I've just posted in the 'Mudcat/Firefox' thread, as below:

Well - it looks like the changes to the page coding to include the 2345, etc calls are also the cause of the aberrant behaviour.

This version of FF (19) on which I have blocked the 2345 addresses works correctly. FF22 on XP and all my other browsers, on which I've not blocked the addresses, behave wrongly.

That's as I find it, anyway.

Phil