Not sure if you are familiar with Galibier cycling apparel from Norn Irn. It was recommended by a Glasgow Audaxer and about a month ago I purchased myself a foul weather softshell jacket. I have used it every day since then on my commuting. I did a 200k wet Audax in it. It is really good for the weather we are having right now (5-12oC and it may rain any time). The prices are very competitive compared to other quality cycling wear.
They also do a waterproof jacket but I haven't tried it, so can't vouch for it.
I am only saying it all of this because they haven't been mentioned here before but this jacket made such a difference in my cycling comfort and it didn't cost an arm and leg.