Fence heights and rights

[Slhinds1]

Hi
I’m hoping someone might be able to give me a little advice, the fence to the left of my house is mine according to the TP1.
The neighbours to the right have recently had their garden levelled which has increased the height of their garden considerably.
They are also having a 2nd fence installed adjacent to mine on their side the issue is that due to the raising of their garden it is considerably higher than the existing fence.
I know the maximum height for a fence but does this consider if they have had their garden raised at all if you see what I mean?

[des8]

Fencing height is generally taken from the natural ground surface next to the wall or fence. If ground level is different on either side of the wall or fence the measurement is generally taken from the highest point. However, where the natural ground level has been raised, for instance to form a patio area the measurement may be made from the original ground level.