32 m is a long run, but the cable is capable of nearer 100m in 4mm with no problems.
I would push for 16mm, but (and I haven't checked the numbers) I had a customer with a long AC feed in undersized, for PV, cable to his barn. When I checked the calculations from basics it only worked at a few watts energy lost, certainly npt enough to cause issues. I that installation, we were on 16mm SWA but with 10kWp of panels and a run of 130m.
"Electrical Safety Officer" sounds like an unqualified sparky to me :slap
I would push for 16mm, but (and I haven't checked the numbers) I had a customer with a long AC feed in undersized, for PV, cable to his barn. When I checked the calculations from basics it only worked at a few watts energy lost, certainly npt enough to cause issues. I that installation, we were on 16mm SWA but with 10kWp of panels and a run of 130m.
"Electrical Safety Officer" sounds like an unqualified sparky to me :slap