Okay, short history lesson;
In the 60's the British introduced the DPM pattern (Pattern 66 and Pattern 68). The clothing came in a temperate (heavy) and tropical (light) material and were issued accordingly.
In the 80's they revised the DPM pattern (Pattern 84). Again, clothing was issued in a temperate* and tropical material and issued accordingly. *note, the temperate P84 was not brilliant quality and often sewn together poorly.
In the 90's they tried fixing the problem of Pattern 84 with Pattern 94, which was EXTREMELY short lived as they introduced the Soldier 95 (S95) program the following year.
Soldier 95 consisted of a complete uniform, designed to be layered (much like the American PCU). It includes a lightweight base layer, Goretex layer and windproof layer. Since S95 was introduced, S2000 has also been produced with a more durable fabric, but still lightweight.
Hope this helps you.