Beko WME7267W smells rank after washes?

Hi,
i have just bought a Beko wme7267w and there is a strong smell akin to cat pee (to my nose; similar to hot electrics; same smell as an old bakelite light fitting when it got hot i remember from years ago.)

Washing machine works fine and there is no smell on clothes or on the waste water.

I've done a number of 90'c cotton programs with detergent but no clothes as per first use instructions and some regular washes and the smell has diminished but still there.
gets stronger as the machine cools down.
I can't pin down where the smell is coming from apart from the back and it seems, the emptying hose.
I did get whiff when i first unclipped the hose from the back of the machine when it was delivered, but if you smell the hose & outlet, there is no smell!

I called out their service rep, but sods law the smell had dissipated by the time he got here and didnt re-occur while he was here, so couldnt pinpoint it.
Had the top off and back panel, but no joy.

The hose discharges into a upright pipe with u bend at the bottom (same as my previous washer of 9.5 years good standing and no smells!)

any thoughts? do i just need to persevere and let the machine burn off oils on components or something?

Thanks