Hi Ton,
I haven't yet studied this version so can't advise too much. This looks like the Tarawa version with the welded hatches, which is fine.
What transmission did you use? They appear to have had the rounded one piece transmission, but I've only looked at a couple of pics so probably had the 3 piece as well!!!!
My advice would be to take a look on IMW site and get a few reference pics to study.
You could add some fittings for spart track on the front, There appears to be a small gap between the transmission and the hull so a little filler there and also on the front fenders.
There's a good picture of 'Aggressor' belonging to A Sqn Staffordshire Yeomanry in British Tanks in Normandy which looks to have the welded hatches and shows several spare wheels on the front and a row of track along where you have your boxes (p62) Check out the picture on IWM B7555),
You cold add a jerry can to the rear LHS and a first aid box to the rear RHS. Agressor seems to be mounting a cabel reel to the top LHS of the drivers hatch. Tow cable and maybe a tarp or some rope to hold down the kit on the rear.
Re: colour of kit, faded OD and cardboard brown for some of the rolled stuff and wood for the boxes with metal bits if appropriate.
Thanks for posting, it made me stop and look up a few things which is useful as my kit arrived to day and I also spotted an M4 Firefly of 1NY which can join my 2 Mk Is lol, lol.
Which unit are you modelling it on. Agressor looks good to me, I might use that one. The 13/18 Hussars also had Mk IIIs.
Sorry I have to go back to sawing resin, hope that helps a bit.
Cheers and Merry Christmas.
Al