@vanHalen We have renovated 2 houses over the years and most of it has been done by us except the kitchen extension where we brought builders in.
A couple of things to consider. We ploughed money into this house to make it into a house that would grow with us. From having a preschooler to an adult child returned from uni and living and working from home whilst saving for their first house.
Long term the house has risen in value anyway but this wasn't about making a profit just about making a home for us. The last house we renovated we sunk £20k into and due to when we bought, the market crash and when we sold we did not see a penny back of that investment. But am I glad we got rid of the horrible green swirly carpets and replaced the leaking bathroom? Absolutely. It was our home for years. How long are you planning to stay in this house?
I have never lived in a Victorian terrace so this might be impossible. I would consider adding another wall (as I am assuming the kitchen wall at the stair end is load bearing) and taking that top area and making that into the toilet area if drains allow, then a new kitchen door a bit further down. That means the door to the toilet is not in the kitchen.
The kitchen length could work in your favour if you remove the conservatory from the back and the toilet etc having french doors to the garden. You can zone the kitchen at the top end and have a banquette seating area near those french doors.
The two things I would suggest, one is to go onto your council planning website, search by map which will highlight all the people who have requested planning consent on your road or in the houses that are the same as yours. Find the side extensions and look at their plans online. Someone might have done something you like the look of.
The other would be to go to an independent kitchen place, get them to plan the kitchen in your current layout and see what they come up with. My friend did this in a teeny kitchen and they ended up removing part of a wall and completely opening up the space. It really worked and is stunning compared to the tiny box she had before. Her layout is completely different to yours though.