So, I took time off work at short notice to wait for the engineer. I should have realised that my hopes were in vain, another no show with no telephone call from the engineer to explain. That makes 3 no shows without any contact so far. I am sick to the back teeth of this palava, as we say in Scotland - 'pure scunnered'.
Just an update to say that I've given up on BT and am having satellite broadband installed on Monday. Now I will wait to see how long it takes to get my money back.
My satellite broadband was installed today - quickly, cleanly and efficiently. The speed is better than I achieved with BT at my last home, so I am delighted. I should have done it months ago!