With a little research I found out that the company responsible is called Acorn Stair lifts ltd
Registered No 03220389
TELECOM HOUSE MILLENNIUM BUSINESS PARK STATION ROAD STEETON BRADFORD WEST YORKSHIRE BD20 6RB
I have reported the Number 015-352-97160
to ofcom. you may wish to do the same.
I rang their freephone number 0800 191919 that they advertise on their website
They said it was 'nothing to do with them' as it was another part of the company, the 'First Contact' dept. I was given the number 01535 291000. When I rang that number I got an automated answer which said I was being put through... but then it just rang out. I guess they were busy annoying other people.
rang the 0800 191919 number again and said I would keep ringing them until they did something... I was told they would make a note of my number and report me for harassment. I can't wait for that call :)
by the way; do not do this