Thanks all, sent enquiries off for insurance to a few providers, all seem much of a muchness.
Boat now purchased. Have previous bills of sales and surveys, safety certs etc. Completely satisfied the sale is fine. There is finance by way of a personal loan not connected to the boat.
Now to sort it out, its currently undercover on a slipway. I am speaking with the boat yard about a few upgrades as the bathroom and kitchen in particular are very tired.
One thing I am going to tackle myself is the electrical system. (I am an electrical/controls engineer). It does not currently have solar, the inverter is underrated and rubbish, no galvanic isolation and presently when the inverter turns on it seems to also turn on the charger. Is there anywhere someone could point me to examples of narrowboat power system wiring diagrams/schemes?