So, has the approach to your property changed at some point? Because I would expect your entrance hall and front door to be at the front and not at the back? Could you turn it around again? If not, maybe move the front door to what is now the kitchen, making the kitchen part entry hall and part utility (dividing wall). Then you could perhaps create one large kitchen/diner/family space from the current utility, office and family room. The current dining room could be an office? Obviously all depending on whether all that would be possible re: load bearing walls and all that.

Thank you for your comments @drpepe101 and @rosemonde. The kitchen on the new plan is how our kitchen is now, the new plan only includes a small extension to the rear. The kitchen is not actually that dark, the back of the house and garden is SW facing so luckily we do get a good amount of light. It also does not feel cramped but that is due to the fact that it has been badly designed with hardly any cupboards - the fridge/freezer and our food is currently in the 'office' behind the kitchen! So I definitely agree that in order to create a kitchen in that space with all the cupboards we need - it will end feeling cramped. I did really want to take out the wall and chimney stack that separates the current kitchen from the office room behind it. We have had three different architects to view the property and they all felt that whilst not impossible it would be a very difficult job. The wall (which is the original exterior wall) is 2 feet thick and is built from large blocks of local stone, as well as having the chimney stack running through the centre all the way up to the roof. I am now thinking the best solution would be a side return extension either for just the width of the kitchen (sketch attached) which would not require planning i believe as it would be under 6m or possibly a longer side return. I wouldn't necessarily need a separate utility if we are widening the kitchen as i could incorporate a washing machine etc in to the kitchen. I would like a downstairs WC somewhere though. Currently our shoes/costs are stored in the cupboard under the stairs. If we went with this layout i would like to create a better opening between the kitchen and existing dining area and put pocket doors or similar in between the lounge and dining room so we can close off the lounge to make it feel cosier when we want to. Will check out the George Clarke shows! Thank you for the recommendation.

Additional photos to show what we think either might look like finished

Personally I think that you have to consider three things. Firstly - given you want new bathrooms and presumably kitchens and carpets etc- how much budget will be left for building work? this will in part inform your plans. Secondly - where is the best place to build?- personally I think you need to consider if the side garden has the best privacy or light and if the overall garden and the windows that benefit from it will be better for building elsewhere. You also need to think about how you intend to access additional rooms and if your current lounge becomes a cut through to another room does that make that room redundant/ feel smaller/ difficult to furnish. You also need to think about the size of the space you have now and how it works for you- so if you make the overall house bigger will the kitchen and dining room feel undersized? Is the idea of the games room to have a family living space in which case it will be best connected to the kitchen or is it that the kids are gamers and a room for that could be in the loft or over the garage or in an underused guest bedroom? Since the first improvement you mentioned was the bedroom would you prefer this to be at the back? It would be useful to have more context and an idea of the size of plot and orientation of the plan.