Congratulations on buying your Avondale, I hope that you will have many happy times away with your tourer.
A common pitfall which affects all pre-owned caravans, not only Avondales is that although the tyres might look as good as new with very little tread wear, caravan tyres can deteriorate though exposure to UV.
The Caravan Club recommends that caravan tyres should be changed before they are 7 years old regardless of how much tread is left.
I've no proof but at a guess I'd suggest that the majority of motorway breakdowns and mishaps involving touring caravans may stem from older tyres deflating or even blowing out, or lack of correct inflation etc.