I'm sure you'll be happy with them GazP, and sorry for not updating – turned out the weather going home on Monday was just windy and not wet!
However, this morning I endured 1hr of constant "light" rain (nothing torrential), which coupled with very strong winds gave the Luminites at least a bit of a test.... I'm happy to say that visibly the water was staying on the outside, and apart from a bit of dampness in the very front toe section (the stretchy bit underneath that hooks over the front isn't the same material as the top), the insides were dry when I arrived at work. I suspect this was caused by excessive spray from the front wheel (had to go through a very large puddle!), so all in all, I still think they're up to the job
Given today's conditions, I'd say they're windproof too – my feet were toasty