Murray, where exactly are these ads popping up..? In the general thread space, or over to the left above the 'latest posts' list. Why I ask is I put Adblock on for a time, but found that sort of barred me from some other sites I use, because they rely on the ads for revenue to run the site, but they only pop up in that left column anyway, so easily ignored anyway. I don't have them popping up in the main thread space, so I took Adblock off. I still only get them in that left column. However, if I access the site on the iPhone, I do get ads popping up between actual posts in the thread space. However, because everything is so tiny in the iPhone I seldom use it to access the forum - would rather use the iPad, which behaves the same way as the MacBook Air I normally use.
So, it might have something to do with your browser settings changing, (eg after an update), and you should be able to stop those ads without actually using a specific app like Adblock..?