PigletJohn, there is no sign of heat damage like on the photo (which I had found in the link you sent), we had that in a kitchen socket last year, so I know what it looks like.
It's an old house, and a lot of work has quite obviously been carried out by unqualified or at least not very competent people, the lino in the kitchen has missing bits from not being measured up properly, some of the walls have been plastered really badly and the tiling in the bathroom was simply put over the old tiling, there are gaps so you can see the old tiling. The plumbing is a nightmare, we have had blockages quite far down twice in 12 months.
And there are 2 other sockets with similar issues, but they are not in use so I haven't bothered asking the agent to fix them. They look old, I guess they could be 40 years old.
(the above makes it sound like an awful house, but it's actually lovely, structurally sound and a pleasure to live in. But like many old houses there is a lot of maintenance)
Pipistrella, I very much doubt that any of my kids have stuck anything into the socket, they are 8 and 11, and they understand that their tablets need electricity to work;)
Anyway, I will call my agent, I just always try to see if I can fix things myself first, as I have never rented a house where I had to call the agent so frequently, and I don't want to be seen as not looking after the property. But I guess I am by flagging problems, it just feels a bit like I am being an unreasonable tennant.