This guy is one of the few Warhammer 40K Space Marines to come with Errant Armour (Mark 8) and is a 1990 sculpt. He’s part number 70106/57 or 070360/1. I can’t find a single sculpting credit for him but I’d be surprised if it was anyone other than Jes Goodwin.
You can see Jes Goodwin’s sketch of Mk8 armour in the Index Astartes Apocrypha book (will be from a WD issue somewhere I haven’t found yet):
I painted this chap up as a squad leader for a Tactical squad, and did his left knee in chequered company colours. A WIP of his knee:
Colours used:
Undercoat: Vallejo Mecha Black
Base coat: Scale75 Cobalt Blue, brought up with Primary Blue, shaded with Prussian Blue, highlighted with a mix of Primary Blue and Art White
Red: Art White, followed by Primary Red, shaded with Crimson, shaded with a mix of Prussian Blue and Primary Red, highlighted with a mix of Primary Red and Orange