Moving the bathroom upstairs is always a great move, as it's far more saleable afterwards as this is what the majority of people would prefer. Also to remove the bathroom and knock through from the kitchen is standard practice in what i presume was a two up two down Victorian property?? Making the bathroom a utility i personally think is a waste of space. Most would choose to simply remove the wall and knock through, then use the whole of the space for the kitchen to include your washing machine / washer dryer - to use the space as just a utility is not making the best of the space available and you don't have enough space to play with. Having a downstairs loo in a 'wee' house ( excuse the pun ) is not a necessity it's just using space you could put to better use. You can then extend at a later date and possibly then put back a downstairs loo. Lots of people would have a galley kitchen with patio doors at the end to give you a view on to the garden. Do you have a plan of the layout? Here's a typical example of such a layout.

Thank you for your replies. Ellie- both rooms are a nice size but we want to incorporate a living area into the mix aswell hence the extension. Also I don't think the current kitchen is wide enough to make that into the dining room Jonathan- I look be the plan but I don't think the dimensions are quite right. For example, the wall where the long side of the sofa is is less than 1m in length so wouldn't fit in the current layout. I hadn't thought about the kitchen to the left side though so might give me more ideas to play with ☺️

thanks for your reply. Yes it is a dark room most of day. Was hoping to have the kitchen extended into utility room and extended into the sunroom. But not sure if allowed to knock down wall at moment till I speak to architect. Be great if we could have a skylight in this room when done. Hope this reply goes to right person

I think if you moved the toilet over to the fireplace wall in the dining room then the dining room becomes basically a corridor between sitting room and kitchen. Having it tucked under the stairs is prob best use of space. Could you not use the dining room as a dining room still, with the kitchen (I assume it's a one wall set up) and island in the kitchen as that is the largest space. If you have pocket doors or barn style doors leading to the sitting room you will save a lot of space for the dining table. Agree with Rinked that more light would be a good thing. If no scope to put in a rooflight could you break a window(s) either side of the fireplace?