Here are some pics of what i imagine the layout to be, really need assistance as this is not my area of expertise.

You will need planning approval for a dormer on the front of the house. It is worth calling your local planning department and asking whether they might be minded to approve such an addition to a house in your area - afraid planning departments often wont approve dormers to the front of a house. If you are in the conservation area you will probably need planning permission for any works to the house. If your house is not listed and not in the conservation area it is worth investigating maximising the space you can add to the rear under permitted development - details can be found on the planning portal https://ecab.planningportal.co.uk/uploads/miniguides/lofts/Lofts.pdf when setting out to do any work under permitted development, for piece of mind apply to the planning department for a Lawful Development Certificate - this is not the same as planning permission but is proof that you house extension/dormer is lawful

I presume that the dormer covers all of the side and goes round? You may try and get permission from the neighbour to change half the front and then change your portion of the roof to match all of yours? I notice that the side of the house isn't rendered, just painted. Therefore, that too could do with being rendered and then the whole thing painted to match, so you could at that point go for a different colour to your neighbour and include the front. Thus your portion of the house would stand out as completely different. Obviously I don't know what your dormer looks like or the exact size and position, so the above is just to illustrate and idea of the different looks achievable.

Hello, We are extending and renovating a dormer which sits above a garage of a 1930's house. Currently the dormer has a slopped roof diagonally across it. Approximately how much would it cost to remove the sloping roof across it and bring it forward to be flush in-line with the rest of the exterior of the house? It would then be like a regular extension instead of a dormer. I've added a photo to help explain the slopping roof, this is of the front, we are extending the back. We will also be rendering it instead of titles. We will keep the flat roof on the dormer to help manage costs. I'm working with an architect but they wont give even rough cost estimates. I'm keen to have a guide if it is big job and the costs before we submit for planning. Thanks!