If someone is in the market for that type if property there is not in a fundamental sense anything wrong with it.
That said, I think you could do quite a lot to improve its presentation for sale.
It looks like you've over "de-cluttered" it in the sense it's lacking the feel of a warm and cosy family home. I know people say to de-clutter your house but so many sellers take this too far. Frankly it has the look of a rental about it given it's so devoid of "family life" and the idea of existing tenants would put people off.
There's a lot of simple things you can do to rectify this - flowers on the coffee table, some simple cushions, flowers in pots at the front etc. Basically just more colour and more "family home".
It's very noticeable that there are very few window furnishings. I assume you have blinds, but again it's a very cold look and again looks very "rental". You can buy meters of cheap muslin and dye it to make very simple curtains (given the blinds give privacy) that add warmth to a room. You only have to hem the top/bottom if you use the fabric width (and given it's for staging they don't even need to close) then thread the top hem on a cheap pole.
I'd absolutely set the conservatory up as a dining room. Presently it just looks like unused (and thus possibly unusable) space.
I'd also think about repainting your kitchen. It's the "worst" room and buyers think £££ when it comes to kitchens, so I'd definitely think about repainting the units.