I'm not sure Theonlysue is the owner of this van and is just sharing the information. Profile shows she has been a member since 2009 and owns a Hymer.Attn Theonlysue.
No doubt you have been reading the responses from members regarding your unfortunate problem and your planned demonstration. Some members in an agreement with you and some suggesting a more DIY approach or acceptance by you to some of the smaller issues you have mentioned.
It would be interesting to hear your thoughts so far.
I can sympathise with you regarding some issues but a demonstration is not going to sort the problems.
A constructive meeting with the dealer is the way forward.