Bingo!!

The actual areas of blistering are magnetic but on further inspection part of the wheel arch is not so a bodged repair is the conclusion

Verified by comparing it to the other side as well.

Thanks you guys for all your inputs .Now to see what the best cause of action is !

So it’s probably a wet sanded piece of body filler that the moisture is leeching out of in the heat. Probably going to be a case of removing the paint, the filler and re-applying. 2012 5.0 SC AB
Mods:
TPMS
Genuine LR DRLs
Remote Boot close from key fob
2016 Discovery 4 Mirrors AKA RRS2
2014 L405 Surround Camera retro fit (WIP)
2013 RRS Dual View Screen fit (Complete)
2016 LR4 RSE
2014 LR4 Homelink
2016 FFRR Electrochromatic Wing Mirror Glass

70 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Those blistered areas are magnetic so oxidisation of the zinc plating caused by its partial removal by sanding/blending in in the repair shop is more likely rather than filler buddy.
I know a local lad whose mustard on panel repair work so I am going to run this by him for a opinion of whats the best cause of action