Totally agree with you, HH5 being heavily promoted on TV now as "the most reliable wireless connection ever" also bt.com/homehub5 - "The new BT Home Hub, Our Most Reliable Wireless signal!". This is 1 hour after mine has dropped it's connection again with no walls in the way and directly in front of me and within 10ft of my laptop.
I was actually ordering shopping online earlier on the wired pc next to the hub which sits next to main feed box (all other internal wiring was disconnected).
I gave up after an hour of disconnections & wife said you'd be easier driving twenty miles to shop than using that piece if junk!!
I am now using my 3 dongle which i pay monthly for & it's performing better than Infinity!!
I would get rid of broadband & landline entirely if it wasn't for Sky downloads i have.
Forgot to add i'm sitting ten feet from hub using my tablet via wifi, hardly live in a mansion 🙂
While you should not have to do this, my advice would be to buy either a decent VDSLmodem/router or an Openreach modem and a decent wireless router and after having fitted which ever one you buy see how far you can throw the Homehub 5.
Which ever route you go down it will cost you about £70 and provided there is not a fault on your line, it will totally transform your Internet experience and you will no longer be subjected to BT pushing software updates that you don't want or any of the other problems associated with the Homehub 5.