Guy

The recognised solution - that the electrician should have known - is to fit a 100A DP fused switch in your external meter box between the meter and the SWA cable to your house. I can't show you a photo of what this looks like as we haven't yet cabled to the house; we have a small CU in the meter box connecting via SWA to the CU in the caravan some 30m away.

I recommend you 'phone your local Western Power (now part of National Grid) office - you may be surprised by how helpful they may be! We had very similar situation, demolishing a 1950s bungalow with the original power cable from the bungalow wall hanging over the driveway to a pole near the edge of our land (thence across an A road to a transformer on another set of poles). We planned to install an external meter cabinet near the pole, initially to supply our temporary caravan, and when we're ready to supply the new house. The National Grid planner turned up for a survey, took one look at the old pole and announced they would replace the old pole and put in new cable from the transformer across the road to the new pole and down to our external cabinet... for FREE. All I had to do was build a wall and install the cabinets (one for their stuff, the other for us) and hockey stick. (And that was my first post!)