I have been reading your post with great interest. As after 3 months of trying BT managed to get the broadband working, I switched from Sky unlimited (non fibre) to BT infiinity 2.
On Sky Copper wire non fibre I got about 12-15mbs.
I am now getting between 13-16mb on the super dooper fast fibre broadband.
I've had a few engineers around and learnt a bit about how it all works, from these forums. I told the engineer I was not happy about the speed. He said he wondered if I was on a 40/10 rather than an 80/40.
I pleaded with him to do more diagnostics rather than leave me at the mercy of the BT cant centre (I mean call centre sorry). I know what you mean about taking a day off from the stress of calling them!
So he used his portable router to test my best speed possible (17mb) and even went back to the cabinet to check and test and he confirmed I am on 40/10 and told me to contact my ISP.
So now I am learning as much as I can before I speak to BT tomorrow.
It seems to me in your case clearly two engineers confirmed your on a 40/10 because of you living on that street and getting higher speeds you know the only thing left to rule out is the telegraph pole wiring, or for ISP to stop throttling your service somehow and move you to 80/40.
The big problem is the disconnet between openreach and BT who seem to constantly be at odds with each other. Seems BT and "experts" on here find it very embarassing when their engineers lets slip information they really do not want the average customer to know!
Where did the engineer get 80/40 from. I thought BT did 80/20 or 40/10 but I may be wrong. Is it also not the case that because Sky and BT use the same infrastructure such as the cables from the cabinet to your house then there would be little to choose between the two for speed. It would also be pointless to go onto Infinity2 if your line can not support any speed above 17Mb. I could of course be wrong and I'm sure if I am somebody will correct me.
I had gathered that it may be a typo but I wanted to point it out because the poster mentioned the "experts" on here find it very embarassing when their engineers lets slip information they really do not want the average customer to know! along with the other incorrect information the engineer told him or rather didn't tell him.