Hmm.
Unless you specified you expected to demolish the existing kitchen external walls to enable an open plan full width extension, I can see a lot of logic here tbh. I’m guessing the conservatory/existing downstairs loo that he’s demolished is an earlier addition that is more poorly constructed/has to go, whereas those walls are original and a lot more substantial? Where’s your upstairs toilet - ie. where is the existing soil pipe? Is that the current location of the boiler as well? What’s the aspect? Is the back of the new extension 6m from the back of the existing lounge, that might be your permitted development limit there, I agree there’s no thought in the kitchen layout itself, the roof light placement seems really random as well, I’d want them either symmetrical or centred over distinct functional areas, but I’d expect that to be finessed as you designed the kitchen, as nothing (sinks/hob) is marked, this plan isn’t at that stage yet.
That window behind the tiny seating area (in reality you’d just have a bigger dining table though wouldn’t you), that could be a full height glass panel, that would be nice.
Don’t knock a big utility, you can have all the messy, fiddly bits of the kitchen in there, appliances, food stores etc, and your actual kitchen will be a streamlined tidy place just for cooking and eating. A sink in there would be good, but this plan isn’t at that stage yet anyway. You could put internal glass above the doors to allow natural light in.
The 2 “front” door thing isn’t such an issue in practice tbh - my parents have this as their utility is a side/infill extension between their house and what was previously a separate garage. You actually walk past the utility door to get to the front door, but there’s no mistaking which is the ‘formal’ front door because of how they are presented, visitors don’t accidentally knock on the utility door, it’s clearly the ‘service entrance’!!! Direct access to your kitchen for unloading shopping etc will be useful.
Many bathrooms I’ve lived with have had sinks under windows as well, we just have a freestanding mirror on the windowsill, it can work very well and isn’t a real issue.
However, this is your home! If you want something that is more copying what you’ve seen on TV, then ask for that. I’m guessing you were thinking side access into a utility/WC and then on into an open plan full width kitchen/diner with an entire back wall of bifold doors and more roof lights as well? Ask for that! Do you not have your own ideas and sketches you showed him first? What were/are your own thoughts?