Thank you all. What I'm understanding (limited) is it will work if the network administrator wishes to make it so.
It's simply that I've been offered some work over a period of time, but for various reasons I do not want to be stuck in a fixed location, nor do I want to have to tell people to contact me on this number on these days, and another number on other days and so on. I realise that a Skype number would provide this solution, but it would look more professional all round for me to have a 'real' geographic number associated to the company. I can do the work from anywhere but prefer people who call me to assume I'm at the UK office and to see that number if I call them.
The idea of sitting in Tableview looking out over the bay and the Berg whilst people think I'm in the UK rather appeals to me!