Just bear in mind that everybody wants 'a deal' these days. It's rare to get asking price - and if you do, it generally means the Estate Agent has undervalued for a quick sale ie no work on his/her part and an easy commission.
If you ask £xxxx it is unlikely you will get £xxxx - most will try a cheeky offer. In my experience ( and I have quite a lot of experience buying and selling) build in a little bit of wiggle room. That way, you are likely to get a price near what you want and at the same time your buyer feels he has got a bargain.
Make sure that any USP (unique selling point) that the house offers is strongly featured in the blurb. 'Quiet neighbourhood' 'near schools' 'nice garden' etc and if other neighbours have extended, then mention that opportunity STPP (subject to planning permission) ......... all these things attract buyers and make a buyer feel his price is justified. Estate Agents often need a bit of a nudge as often you will know the best bits better than they do!
Here in the SE my experience is that internal condition does not have a huge bearing on price - if the building is sound, the rest is merely decoration. A property may sell easier if it is in good condition and has visual appeal - but a house is a house and most will want to put their own stamp upon it. When I sold Mum's house a couple of years back, I just had to make do with it being super clean - it was so dated. If the approach looks tidy and the house looks worn but cared for - it really does help. I was gobsmacked that I got asking price when 2 prospective buyers were fighting over it. Within weeks of them moving in, the place was completely gutted, rearranged and redecorated.
If the property does not sell, my advice is ( if you are able) to take it off the market for a couple of weeks and then advertise anew, at a lower price with perhaps a different agent. That way it will be sent as a new property to all those who subscribe - rather than a property that has been reduced as it hasn't sold.
Don't bother with multi agencies it costs more and is rarely worth it - just check that the agent you choose advertises with Rightmove. In today's world of internet, if somebody is looking for a property they will look there and see the property. If it is listed with multiple agencies it suggests desperation. If prospective buyers opt to visit an area to househunt, most will look in EVERY Estate agents window anyway.
Good luck! (In the same position as you and just about to market Mum's current place).