We have just moved into a 1930s semi, which has been extended in the recent past (I) the garage had been converted into a utility room (single skin extension) and (II) addition of a conservatory onto the living room. We would like to redesign the layout of the ground floor, at the same time as adding a double storey side extension to enable 4 bedrooms upstairs.

Restrictions to any proposed plans are (a) requirement to retain the side access from the backgarden to the front (2) a main drain outside the conservatory doors which cannot be moved/built over (as I understand it!) and (c) the shape of the plot tapers due to its position on a crescent.

We have had some plans drawn up which remodel the existing footprint, widen the house by approx 1 meter and convert the existing conservatory into a room (flat roof with with velux). I would really appreciate any comments and advice on layout and how this space could work for a family home.

I have attached the existing layout and our proposed alteractions and welcome all alternatives!