On Sun, 20 Oct 2019 12:58:45 +0000 (UTC), Brian Reay wrote:

Other things a PCB "conformal coating", sprys or paint on with
small
brush. Flexible to some extent but won'ttake repeated flexing. Or
maybe pot the whole in "Magic Gel" from Raytech.

Conformal coating, such as Humiseal, would be a good choice if he can
get hold of some. I ve never tried to buy it privately/over the
counter, it came across it professionally-

CPC, Rapid, eBay... have Electrolube HPA (High Perfomance Acrylic)
conformal coating. I've used it to protect the components and PCB
inside a tiping bucket rain guage. Other conformal coatings are
available based on other materials like silicone.

Further info from the OP indicates that the wires have to flex at
least 90 degrees and I expct in quite a short distance. Not sure HPA
would be up to that, other formulations might be.

--
Cheers
Dave.