But they have done something to it, CFS - I seem to recall them saying they had rewired, replastered, insulated and of course redecorated.....
However, none of these things are obvious unless the EA points them out. Things like new kitchens, bathrooms, extensions are more obvious 'improvements' but the OP hasn't done any of these. Unfortunately they too are the things most likely to add value - although even fitting a new kitchen doesn't a,ways gave the desired effect as it may not be to every buyer's taste 
I do agree though that being able to see what was paid for the house in 2014 could be a factor - and the fact that to some potential buyers the older incarnation of the property is more appealing and perhaps the trend for grey everything hasn't extended that far north?
When we sold our last house in 2014 there were no historic pics available online - just the price we'd paid in 2011. We were now asking around 150k more than that, so some potential buyers may have thought we were hoping to make a fast buck......whereas in actual fact we had extended, rewired, replumbed, replastered, added three new bathroom/shower rooms, relandscaped the 1/3 acre garden and redecorated throughout the house was an unmortgageable wreck when we bought it so we jolly well made sure our EA had all this info in the details online etc. The price we sold for was 135k more than we'd paid - a 'profit' of around 35k on top of our costs to do the work.
Photo-wise, our EA was a fan of the less is more school of thought and we only had about 8 - 10 pics on RM, Zoopla etc, but they did have more on their own brochure. They believed not putting up pics of every room was a way to entice viewers to come to see the property in the flesh, rather than being able to see it all online where they weren't getting a true feel for the flow/character that the house offered.
Again I want to add that many period houses have a similar layout and imho those that love characterful properties will not be put off by quirky layouts/rooms leading off other rooms!