Route supply to garage along a cavity wall base?

[epsilonGreedy]

When my house and garage footings were built I incorporated an underground cable conduit to bridge the 1.5m gap between the house and garage, (yellow in the plan view diagram below). However I have decided to dig a separate trench for the 240v supply and use the conduit for only Ethernet lan cable and BT telephone. This change of plan is due to a concern that running 240v mains and data cables through the same conduit risks degrading the Ethernet data speed.

 

The second diagram shows the cavity wall footing detail for the dividing wall between the garage and workshop. My hunch is that it should be ok to run the 240v feed to the garage CU 2 along the base of this cavity because the floor level on either side is high and offers protection against a future DIYer with a drill.

 

Would an electrician sign off such an arrangement for a new build?

 

The cable will be armoured with a 25 amp or 40 amp capacity.

 

Edit: The green bock below is the cavity fill at the base of the cavity.

Edited June 13, 2021 by epsilonGreedy