I find your program is pretty much what i'm looking for, but I have a number of questions that I need answering:
1/ It is very important that my customers can contact each other instantly on line (not via email), is this possible. Obviously both parties need to be online at the same time.
2/ Can I add or remove customers through the admin section instead of them going through the normal channels on the site, for my family & friends, etc.
3/ I have more than one website, can I use the program for each site or do I need to purchase the program for each of them.
4/ I am based in England. Does anyone know of any problems that may occur from being England based.
Many thanks.

[juven14]

/ It is very important that my customers can contact each other instantly on line (not via email), is this possible. Obviously both parties need to be online at the same time.

No, the system currently just allows the email to be sent via a form.

2/ Can I add or remove customers through the admin section instead of them going through the normal channels on the site, for my family & friends, etc.

Yes, you can see how this works in the demo

3/ I have more than one website, can I use the program for each site or do I need to purchase the program for each of them.

You can have as many installs as you want per domain. You'll have to buy a new license for each domain.

4/ I am based in England. Does anyone know of any problems that may occur from being England based.
Many thanks.

Well the zip code module won't work for you, but as far as I know that is it. I know there are several uk 68 Classifieds sites so I'll let them comment further.