Hi, a newbie here...
I've read about the Morrari before and its great that you're trying to recreate one - but PLEASE don't chop up that lowlight!
Look at the pictures - the Morrari WASN'T based on a low-light Morris saloon! You can tell because the Morrari has a 'swage line', a body moulding, running from the back edge of the rear side windows, from side to side, below the back window. The early Morris saloons, like the yellow one you have there, DIDN'T have that. For some reason, after 1950 when they raised the headlamps onto the top of the wings, they altered the rear edge of the roof panel to have this moulding to separate the roof from the body tub. I hope this makes sense!
Racers in the 50's and 60's used to retro fit the low lamp wings to aid aerodynamics. The Morrari was a 1950-53 saloon - it has the swage line I mention above and also had the early bonnet shut line which changed in the 50's - the later cars had a bonnet that reached right back to the base of the screen and the window gutters.
Please don't chop up a very rare early survivor!