Looking for a great telephone conversationalist

My company is looking for property in the UK. I need somebody based in the UK who could make phone calls on my behalf and be able to clearly explain what I am looking for and what are our requirements.
No special skills needed, but I would prefer if you had experience in telesales, sales, or just be willing to push my idea when speaking to the contacts.
The main difficulty of this process is that half of the contacts will not understand straight away what we are looking for, so the person doing the phonecalls should be able to explain and, hopefully, convince ;-)
I will supply you with the list of estate agents who I want you to call, and will explain you what to say, etc.
All you need to do is to ask if they can offer what we are looking for, and if they can fullfill our requirements, get there contact details and pass them to me - I will do the rest.
Initial job will be a couple of hours just to see how the applicant deals with the task. Obviously it has to be done during working hours. Your location in the UK doesn't matter.