Thinking ahead to the colder months and I want to purchase a decent running jacket (around £100 mark).  Any suggestions/recommendations?

Personally, I wouldn't bother. I just add a layer or two of tops - base layer, long sleeve top(s)... and hat/gloves/tights.

I always end up soaked in sweat, so fresh rain water is actually an improvement! A water- and wind-proof outer just increases sweat levels.

I dare say I'm in the minority though, as usual!

That's two out of four, so not in the minority - yet!

I'm a jacket fan! I use a cycling jacket that is quite snug and has a loop on the collar to which I attach a red light for night time runs. If it is likely to be warm then I just wear a long sleeve base layer under the jacket. The jacket has a full length zip, vents under the armpits and a slashed vent across the shoulder blades so it is quite easy to regulate the air flow. I think I only paid about £45 In Evans Cycles

I found that if I run in tops they absorb the water, get heavier and I get chilled

I swing both ways so to speak. I have a lightweight jacket but hardly ever use it as I use the layer system, long sleeve shirts so I can take them off and tie 'em round my waist, then when I cool off put them back on.

Prbably used the jacket 2 - 3 times over winter when the wind was cold and cutting not because of the rain as moisture does build up on the inside and you do get wetter then you would have without one.

Swing both ways!? I knew there was something funny with your gait!

Aye!!