Dear Briain,
I agree with you, but some of us do use the Sophos UTM for business purposes to protect their networks. You also pay quite a decent fee for this. I therefore expect quality from a supplier like Sophos.
Personally, I can't estimate the effort involved, but I find it amazing that there are still no further results from Sophos. I also know that other security solution providers are not really any further along.
So I think we will all have to wait and see.
Best
Alex