TY, your problem was that the DA42 was classed as a 'means of transport'. In EU law this is an aircraft with a MTOW of more than 1550kg. If it were less than 1550kg it would not fall under the Notice 728 definition. Consequently, your work around relied on the ac not being 'new'. Alternatively, an ac with a MTOW of less than 1550kg is classed as any other intra-state purchase where the chargeable rate is that of the country of sale and not country of destination.
See here -
http://customs.hmrc.gov.uk/channelsP...yType=document