Folland Gnat

Hi Guys,
Have recently got the new Airfix 1/48 Gnat, and intend finishing it in the silver / dayglow CFS scheme.

My question is this. Looking at the fairing / bulge on the fuselage, where the tailplane joins the fuselage, on some aircraft thefairing is painted Dayglow eg. XS105.

On other aircraft. the fairing is clearly painted silver eg. XP501.

Can anybody confirm which is correct for XM709 as featured in the kit ?

Thanks in advance.

Cabbage