For clarification, I haven’t spilt water along the skirting board, that wet patch appeared of it’s own accord.
And sent me into a bit of a panic. I began to look further and discovered more damp patches and on Monday called a few companies and got them to come over and take a look.

Three companies came over. The first poked around with a damp meter, looked at the window seals, the (lack of) vents, talked about condensation, looked in the half cellar, checked for cracks and leaks and said he’d put a quote for a new damp proof course (dpc) out in the post.
The second company was a man in a suit, who tapped on the walls, used the damp meter to show me that where the wall paper was dark it was damp and talked extensively about salts, replastering and this ‘new’ cream dpc which his company could provide me with.
The third company was a man in a suit, who again tapped the walls, told me that the wall was damp (surprise) and said authoritively that it was ‘rising damp, because it’s damp at the bottom but not further up’. His company could offer a revolutionary, ‘green’ solution to damp using a process similar to the schrijver system which dries out the wall using evaporation. – Upon enquiry, I found that he used to be an estate agent.

What has all this got to do with sustainability I hear you ask. Well, quite a lot if you put in damp proof courses which aren’t needed or don’t work. Because the thing is, although there is the damp shown above in the house, there is also this sort as well.
Ie there is mould and there are wet patches. Separately. Now it doesn’t take a genius to figure out that these might have different causes, given that they look different.

So I started to investigate damp.
First, the schrijver system. This interested me – it seems logical – increased airflow makes the water in the wall evaporate. However, if this is so successful, why haven’t people been putting holes in walls for hundreds of years? Answer: it probably isn’t that successful in most cases. A useful summary of the problems with this method can be found here. Certainly not in my case where there is internal rising damp as well as external (the salesman’s solution to that was to paint over it).
Secondly, the silicone injections. Well, if the damp course had been breached and the problem was rising damp, they are the best available solution. However, if the damp is coming from condensation (water in the air condensing) or penetration (water from outside getting in through a crack or similar, above the dpc) then protected against rising damp is not very useful (more info here). And that’s beside the problem that the silicone may not ‘diffuse’ far enough to create a complete layer, rendering them not very effective (see here).

So after some self diagnosis helped by this site (ignoring the selling aspect) – I now think that a combination of condensation and probably penetration because of the crazy amounts of rain we’ve had recently are causing my damp. Therefore like so many things, the reasons are much more complicated than I first realised – the pointing, render, possibly a small leak and the lack of venting all contribute. Silicone injections and air vents in the outside wall both look like easy solutions by comparison, but that’s the point isn’t it? Reality is always more complicated and any instant fix is usually too good to be true.