Pete Hi,
The HENG LONG Control board is a 2.4 GhZ Digital unit and unlike the earlier 27 MhZ crystal driven unit it does not need an external aerial, So if it is in the correct location for a Challenger 2 aerial leave it alone except for a brush stroke of Matte Black.
If it is in the wrong position then either relocate it or simply remove it,
It serves no purpose other than to poke out the eye of an inquisitive child or dog.
Shaun.