Nibbie
I have first hand experience of this getting out of hand.
Son, then aged 18 and in his first brand new house, rang to say that he couldn't get rid of a double glazing salesman (same name as a religion) who had been with him for 4 hours.
Was quoted £16k for 2 front windows and door.
Guy went outside (to call manager...lol) came back with offer of £12k as long as he agreed to put sign up on his lawn.
House is at end of small very rural cul-de-sac of 10 with no passing footfall, so an ad board would be useless.
The house was was less than 4 months old and already double glazed, although my innocent son had no idea what double glazing looked like at that time.
I asked to speak to 'Darren' and told him that he had no right to be preying/ leaning on my son and I wanted him to leave whilst I was on the phone and not to phone or contact him again...or else.
I myself have had bother with this company recently and one salesman said that, unless I said yes and agreed to the price (for 1 window) over the phone, that he wasn't going to 'even bother to waste £40 in petrol' to come and view the window in question. I had 4 cancellations from different salesmen before that conversation, with excuses ranging from 'a family emergency' to 'being off sick'. Phone calls to see if I was still interested, continued for the better part of a year. I threatened legal action. They stopped.
I went with a small, family run local company.