I’m having exactly the same conundrum with a Rab eVent jacket.
It seriously pisses me off that the manufacturers don’t give you more info on the care of the product. I’ve used every ‘tech wash’ available (well, Grangers and Nik-Wax) and also Grangers XT Proofer. Non-the-less, my jacket wets out immediately and is massively sweaty.
In an effort to restore it I followed eVent’s advice and washed it in a liquid detergent. WRONG!! Apparently I didn’t guess right, and by using a bio detergent I’ve now made matters worse. Brilliant.
Now I just need to wash it again, and again, and again, with Grangers, then use the rest of my bottle of spray on proofer, and tumble dry it, in the hope that my 6 month old, £200 jacket actually keeps me vaguely dry. 👿