Got the guards rolled today and it make such a difference.
Lesson Learned. Trial fit the wheels and tyres before driving away! I thought the +45 offset would be ok without rolling. That was the advice from MSWT, but the reality is they assumed I had standard suspension. Not sure even with standard that 19x8 will fit. To their credit, MSWT also explained that the Kumho Tyres (225) are a "wider" profile compared to other brands, but still not convinced. Diligence was lacking on both sides, I should have done the calculations more diligently, but in any case, trial fit prior to purchase is today's lesson.
So 19x8 rims with +45 offset and Kumho KU31 ECSTA SPT 225/35 R19 88Y tyres and they would not fit the 3.0R without rolling.
All good now though, thanks to Gavin at LowDown (see dedicated thread for Guard Rolling).
Man, those wheels look good!

MY15 Jaguar XFR-S 5.0 V8 SC 8AT White Saloon (Stock - nothing more to do with 400+ KW

)
MY11 Jaguar XFS 3.0DTT 6AT White Saloon (Prepped for sale)
MY19 Subaru XV 2.0iS the shopping trolley and weekend all terrain cruiser!