Oh that sounds rough. luckily I was told that it could just be a 3cm channel under the paving slabs or if I cut off the edge of the paving slabs it could go down the side.
How deep does it have to go? It sounds like one of those things that by the guy with a digger gets to you, you could dig it out by hand! Depending on dirt type. Ours is fairly easy to dig.
Annoyingly I found that the originals cable had failed as it was two bits joined in a metal box full of water under ground! I think we could possibly reuse it but the sparky suggests running a new higher amp one.