Speed Limit Signs Unclear

There are at least two 30mph speed limit repeater signs between the A4130 and the top of the hill at Nuffield. Coming onto Nuffield Hill from the A4130 there are no gateway signs to indicate a reduction to a 30mph speed limit. Equally, coming down the hill from Nuffield there is national limit gateway signage. I suspect either 30mph gateway signage is required or the repeater signs that are present are unauthorised. I would at the very least appreciate clarification of the correct speed limit foor this road.