Hi Andrew,
She's a fine beast matey! A wash would be beneficial but it's best to get some build practice in first. I wasn't sure if you had any wash/filter experience from your other work.
I make a lot of my own washes from Windsor and Newton Oils and Mineral Spirits but I also make full use of the MIG range of ready to go washes and filters. They are very good imo. You could perhaps start with them. I'll happily give you a step-by-step guide to painting, filtering, decaling and washing.
Note: Bullet, nothing wrong with my barrel as such but where the two halves join is really bad. They sort of 'dip' inwards at the join so it's nigh on impossible to get rid of the seam! A 1/48 replacement Aluminium barrel is about £2.50! I had a slight 'mishap' with my barrel yesterday so I've got another coming in the post today so hopefully WIP can continue later on after the postman has been! I had planned to have the base coat on by now!
ATVB
Ben 