Country Covers Waterproof smock/Parka

[KAE1]

Hello all,
Not been on here for ages but I know someone will know the answer to this......

I've just bought a CC/Arktis Waterproof smock/parka and on the first time I've worn it I've leant onto a painted (gloss) doorframe. Gave it a good scrub and got paint off but have lost the outer water repellent. Anyone know if Nikwax Tech Wash is ok to use on this fabric.

Thanks
Keith