Given the substantial nature of the boxes, and the fact they've obviously been there for some time, I'd take a guess at real transformers, as opposed to modern SMPSUs. Most likely for ELV lighting.
Sorry for the long delay in response, been a funny few months. This is in domestic premises and three of the four seem to be active. The fuse box is still old with Wylex BS3036 wired fuses.
There are only three downlights in the hallway and all the rest are standard pendants in this property. THe client stores bikes in the coal shoot, so I thought it would be best to mechanical protect at least the cables but I think she wants it all out if of no use.
All cables in and out all ook to be 1.5mm so lets hope they are only attached to lights ..
I am back in there on Saturday so I will pull some fuses and see what goes on and off. I will update as soon as I know this time
Update - so it turns out they where Low Voltage Transformers. And once opened quickly worked out they where no longer in use and where being used like connection block lol