Thanks again to all for your comments, and particularly to you Mike H, for being so generous in saving me £3K.
In my humble opinion, it would seem to me that you are all right. As without the right marketing, you don't get any customers, and if your not a good carpet cleaner, you won't keep them.
Your theory Mike, about your three mile rule is interesting. It obviously works for you, so I think I will start from that point, and see where it takes me. I could always look further afield if it wasn't working for me.
Regards
Martin S