For me I don't bother about manufacturer customer service when there are issues such as broken parts, missing parts. You contracted to purchase the plane from the hobby shop. Why not get the hobby shop to resolve things with you? If the first broken plane is not of merchantable quality, that is if it really broke due to the plane not being good enough. For the second plane, they (LHS) sold you an incomplete plane. Return the second plane and change it for a new one. Am I missing something here? Its just basic consumer rights and contract law.

Dude ... you are British ... there is the Sales of Goods Act, implied terms as to fitness for purpose and also sales by description. Then you have the Consumer Protection Act there too. Unless you purchased the plane from the US then you might have issues ... Remember you handed cold hard cash to the hobby shop and not the manufacturer. Keep that in perspective.