How do I bathroom / kitchen / extension? etc.

I don't really want to do the full width extension off the back. I think it would destroy the charm, and robs light from the reception room and morning room.

If you mess it up, then yes I guess that's what will happen. Trick is to do it and design it so that you get what you want :)

We would move the kitchen into the morning room, and have sink, fridge, dish washer, washing maching tumble dryer, in the new extension.

I hope you would do this in such a way so that the dishwasher and fridge are auxiliary and the primary appliances are in the kitchen in which you'll cook. Otherwise the usability of your kitchen goes out the window (nearly literally!) as you are moving to a different room to load your dishwasher and get ingredients from the fridge. You know that, though, right.

If it was my place and I really didn't want to have a larger extension to the rear I would make sure the kitchen I put in to the morning room has every essential appliance in it - fridge / freezer / dishwasher / oven / hob / sink. Then I'd have the the lean to extension as storage & utility, washing machine, dryer (stacked on top I guess), storage freezer if required in there too, and I'd keep the sink if I could as well as storage space for boring shit.

I wouldn't bother re-doing the lean to because by the time it's been re-built to regs the internal area will be possibly be even lower than it is now (insulation, heating) and it will have a felted flat roof which will probably fail in ten years time. There's something to be said for a pitched roof with tiles. I'd just accept it will be cold and uncomfortable in there.

I think it will be really tough squeezing a great kitchen out of the morning room. You'll probably find you need to take the chimney breast out so that stuff will go in and of course that means removal elsewhere and reinforcement. You can't knock a big portal through to the extension either without reinforcing the external wall too, so that's not going to be cheap. Maybe knocking through the two rooms at the back is the way.

It's a lot of time / money / effort to get something that will probably feel OK if done well. This is the thing with that house - nothing will be cheap and unless you go balls deep it could be weird.. Like, do you want a downstairs loo that you don't have to leave the building to access? Good luck...!