I used to do a full load survey and calculate it all but after speaking to the planners at the DNO they were much more relaxed, they said main things for them were for a typical dwelling ignore the lights, allow for the sockets if lots of appliances,
Major things to allow in your calcs were electric showers, induction hobs, ovens, hot tubs/spas and specifically welding equipment!
they take view that the current method of calculating MD is outdated for average homes these days.
I just give my rough figures now on the notification form, and attach images of the board with mcbs, image of cut out and details of large appliances. they have said they find that much better than a rough or 'calculated' MD figure.
An example - I calculated MD recently for a friends property and on paper you would think it would be drawing over 70A - kept my clamp meter around tail whilst on site surveying and catching up, when i left I looked at the maximum measured value and it was just over 30A in that time oven had been on, kids showering, appliances on all over place. kettles boiled, etc typical use with a family with teenagers who have just got home in the evening.
