if it’s materials and labour get your sparky to purchase conduit. If he buys far too much he can retain the surplus.I have fed A large number of 2 x two.5mm T&E drops down 20mm oval conduit drops, without the need of resorting to any lubricant, but only at any time with picked would make of cable and conduit. Prysman and M/Tuflex recently.Many th