This is where I have ordered mine from, nowt to do with me as a business https://www.britishmilitarysurplus.co.uk/
You've converted 3 people now, my jacket arrived today,a blue RAF goretex one in new condition and for only £19, cheers stinger.
In the summer i pack a pair of Browning's fishing unlined 100% waterproof trousers. In black only. Made by Regata. Cost me less than a tenner from eBay shops. Used them for fishing and biking and have never let me down or wet. For an unpadded waterproof jacket, i got one from go outdoors. Hi-gear make for about £30. Both have kept me bone dry in the last few years. A plus is I've just found out that folding them up tightly, both fit under the seat of the Tiger
Proof.....who needs Gor-Tex I was as dry as when i left home when the sun was out . so glad i had boxes on the bike for my TT100s and council issue wet gear