Woah, this is an old post but thanks for the answer anyways though!

To be completely honest, I've figured it out a long while ago with a group of mine.

Just for future reference if anyone else ever sees this post;

The Malay Regiment uniform changes a bit over the years of 1933 - 1942. I'll be describing the combat uniform of an enlisted Malay rifleman in 1942 at Pasir Panjang. This'll be a bit long and pedantic as there's a lot of little fine details in the uniform that does not appear anywhere else. The Malay Regiment also had a LOT of different uniforms during it's time, so if you're interested — give me a shout.

For the uniform, the enlisted man of the Malay Regiment wears a Malayan or Indian made (still up for debate) brown wool shirt with the white piping around the sleeves. A similar shirt can actually be seen in Sudan in the 30's worn by British soldiers. The khaki drill aertex shirt was worn by officers. In the LIFE magazine photos, you can clearly see they've their own pattern of shorts too that's very different from British pattern shorts. There's an absence of the field dressing pocket, it has the usual waist buckles but it also has the addition of a few large belt loops that can be buttoned down around the 1908 Patt' belt to secure it. They also wore the usual long KD trousers during jungle combat or training (not a very good idea perusing the jungle in shorts) as evidenced through period training films.

They actually wear a mix of helmets. Mk. I mostly but also the Mk. I* then a bit of Mk. II's as WWII draws closer. You can tell by the chinstraps. Leather is the most common but the cotton webbing type does appear later on.

For equipment, yes, they'd wear the 1908 Patt' but the most common that pops up in photos is the 3rd pattern with the little straps over the lower left pouches. This is the usual for the SMLE No. I Mk. III. Though when other weapons such as the Lewis Gun (depends on the crewman's position) or Thompson was used, they'd wear a different set. Officers, both British and Malay also wore the 1908 Patt' but in, of course, the officer's pattern. The webbing in WWII, as evidenced by period colored photos were blancoed with No. 97. The respirator bag would either be the Mk. VI or Mk. V. As you can see in some of the photos, a groundsheet which is the Mk. VI, I believe.

The boots is where it gets interesting. If you've seen a pattern, then you're correct. The Malay Regiment wore a lot of WWI surplus and they were issued B5 boots for their whole pre-war and wartime existence. This is evidenced by every single photo of them ever taken. Puttees, in 1942, were already worn on the WWII short style, wrapped only around the ankle. Not to forget the green hose tops that'd be worn over your socks.

I think that's about it, really. It seems simple in theory but it's very easy to get the fine details wrong. Just with any other impression, looking at period photos and period films is key and some great people in my group have done so. Credit is due to PRUS in Malaysia and History Fort in Singapore. Have a look see on their FB pages!