The fact there is no makers name and the position of the holes makes me think it is?

I had the same thought.

I don't think so, the mounting holes being very close to the edges is usually an indication of an original, as these were drilled before the steel went for enamelling. Unfortunately I've never seen another one of these in any book or in the flesh so no comparison can be made. I suspect it was for the Irish market. Maybe ask the seller for a picture of the reverse side which may reveal if there is any enamel overspill on the edges which also will give a good indication of an un-molested sign.

still nice though