What type of aerial socket/connector is this?

That's beyond my expertise. From its description it would appear to be universal, i.e. it doesn't matter if it's not the same make as the masthead amplifier up by the aerial. But don't take my word for it.

[nodrogd]

Yep! I had the feeling it would be something like that.

You can just see the MHE, which I have circled in your pic. The Log Periodic aerial up there is good at discriminating against unwanted signals, so there must be issues in your area. However, despite it's size, it does not perform well in low to moderate signal areas, requiring an MHE to be fitted to the system. The majority of them run at 12v, so should be compatible, although using the original would be preferable.