Repeater signs inconsistent

North and southbound along this stretch of the A340, the road signage is inconsistent. There are national speed limit repeater signs a short distance before and after a new 50 sign. The 300-100 yard signs are in national speed limit colours. Northbound there are several national speed limit repeater signs. Similarly, on the approach to the roundabout with the A339 (so northbound on A340) the 300-100 yard signs are in A-road colours, despite being a national speed limit road. This causes a lot of confusion as to what speed limit actually applies.