Rolls Royce just about to eat lunch !
 

STOP ! please dont eat my A8

http://i60.tinypic.com/2dtaqf8.jpg

That looks massive.

Is it that big in comparison to the 8 or some camera trickery?

Not much bigger than the A8. Clever camera angle, and optical illusion.

They are still bloody big in length and height though if you stand next to one!

Probably thanks to the massive wheels and 2:1 wheel-to-height design ratio which Rolls Royces have been built on since the 1930s:

http://i60.tinypic.com/1685z0x.jpg

Rolls Royce Wraith:
Wheelbase 3.45 m (136 inches)
Length 5.15 m (203 inches)
Width 1.87 m (74 inches)
Kerb weight 1.9 tons (approx)

Audi A8 D3:
Wheelbase SWB: 2.94 m (115.9 in)
LWB: 3.07 m (121.0 in)
Length SWB: pre 2007: 5.05 m (198.9 in),
post 2007: 5.06 m (199.3 in)
LWB: pre 2007: 5.18 m (204.0 in),
post 2007: 5.19 m (204.4 in)
Width 1.89 m (74.6 in)
Height SWB: 1.44 m (56.9 in)
LWB: 1.45 m (57.3 in)
Kerb weight 1.6–1.9 tons (3,682–4,387 lb)

so the LWB version is actually bigger than the roller, albeit not by much, it must be one of the largest cars on the road, the lwb new sclass merc is 1 and half inches longer, but there cant be many others.