There seems to be a lot of tin pot firms out there, even with the SIA. I work for a large company as a Patrol & Response officer. In my personal opinion, you need to go with a large company. Our prices vary from £300 - £500 per year for keyholding with no call out charge to just call out charges of between £30 - £50 per hour.
some smaller firms do have a dedicated service,aswell.
charges vary mostly who the client is and how far away and how big the premises,we charge 15£ for a lockup/opening.20£ for an alarm response,in the first hour thereafter 15£ for every other hour.contract fees about 150£ varies depending how many keyholding sites the client has with us.