There doesn't seem to be too much wrong with your home. It looks big enough for you all at the moment, obviously when the children are older they would probably like their own rooms. I don't understand the "guide price", this would indicate an auction sale and there is no mention of one in the details. If not going to auction you would be better saying "offers in the region of" or "offers over". An auction can put off some buyers. Where is the off street parking as from the satellite image the garage appears to belong to next door, unless it is right in front of the house.
The front of the house is a bit boring and needs brightening up. If window boxes aren't an option then some tubs or big pots with bright and cheerful plants. Also from the photo the flag stones look to be a green and possibly slippery, a quick powerwash would help.
As your house is on a little side street there won't be any passing traffic so is there a for sale board on the main road? Some people cruise an area looking for a house and wouldn't necessarily look down a small street like yours.
One thing missing is street view of Higham Street, ask Estate Agents if they can sort that out, although it might not be possible. I have been house hunting for best part of a year and it is good to see the property in its locality. It can save a lot of time travelling if you don't like the look of the area. Also in the photos there are a few personal things around like pictures on the fridge and photos. Some people don't have the imagination to see themselves in a place if it already looks full of someone else.
Unless the agents have added the floorplans in the last couple of days they are very clearly there, both at the end of the photos and in their own right.
Possibly ask the agents to organise an open day/weekend, put on tea/coffee and nibbles.
Also approach another estate agent - it never hurts to get a 2nd opinion. Maybe try a national one.
I understand you would like to be nearer to your family, but it wouldn't be the end of the world if you took your house off the market and tried again at a later date.
Hope you get a bite soon.