Oh, I do not think CB will design with a 10m run between ASHP and hot water tank. 10m is the maximum specified by, for example, in the Vaillant installation manual. A long pipe run like that, I think, will hit efficiency but if it is designed carefully with few 90deg bends it should work OK.
Anyway, I believe none of the big players like BG, EDF, Aira, Octopus will do accept 10m. They will push you to have the ASHP closer to the house.
Anyway, I think CB have several designers in their team and I would suggest you keep a close eye on the design details and heat loss calculation.