I done quite a lot of new builds, with the price of gear it’s not a cheap hobby these days, but if you got the land already and did nt have to pay for it with planning in place you are in a good position. But it’s about 1 year depending??? Of hassle and agro if you build unless you got a friend who’s good builder. Planning only is just the start tho, you need building regs drawings, building inspector on board, may well need soil sample sent of for structural engineers to design foundations could need pilling which is top dollar, then structural for beams inside etc, you may need sap calc fo