Speed limit recognition system

[Ant555]

Im wondering if my speed limit recognition system is faulty or just rubbish?

When driving, I get that it may 'see' side roads and note the speed limit (20, for instance), but mine is completely hit and miss and shows random speeds when driving down a road with no signs.
It regularly says 20, 10 or even 37 when driving along roads (even the motorway!)

Ive cleaned the windscreen but im unsure if there is much else I can try apart from taking it back to the dealer which is a pain as its only 2 weeks old and the garage is a trek away.

It wouldnt be so bad but it beeps and bings when im driving way under the actual limit because it thinks I am in a 10 zone (I mean, how many 10 zones are there in the UK apart from random car parks)