Thanks to everyone who has responded.
I did contact the pacemaker team yesterday and they said that it would be okay to go ahead with the dentists but to speak to the Consultant before hand. I also thought that if my appointment time is not first thing I may be kept in overnight, as I know the date of the appointment but not the time.
So I will have to contact the dentists and wait even longer for this dental work to be done now as I do need to get the pacemaker fitted. The reason that I am getting fed up with this is that I have had to wait 3 months for the dental appointment and have now heard that the dentist is also leaving..........