On the Dutch side, things are not so easy (as expected). Nobody in the IVW (Dutch equivalent to DGAC) could tell me they were the right person to inform me about this subject matter,
I cannot see how in the UK the owner could be prosecuted if a renter breaks the law and the owner knows nothing about it. But the Netherlands might have such a law.
Over here, the owner/operator is strictly liable (which basically means he has no defence) for damage caused on the ground in a crash. Normally the insurance will cover this but if the renter had e.g. a fake license (which is not at all uncommon; lots of people boast about having such and such papers, and I have even known instructors with bogus qualifications) the insurer won't pay out. If the pilot's medical has expired by 1 day, they won't pay out. Aviation insurers normally pay out without much trouble but won't if the flight was illegal before it got off the ground. This is basically why most people renting out their planes do it via a limited company.
and they also mentioned the Belastingdiesnt (Dutch Tax Authorities) requirement to be informed of any "revenue generating activity" so, it seems from the Dutch end, they've scuppered my plans.
You need to see an accountant.
But there is a basic principle here. If they tax the income you are making, then they are classifying your activity as a
business (which incidentally is not the same thing as employment) which means that you can offset your operating costs against your income, and you pay tax only on the net taxable profit.
And I bet you that any accountant with 2 braincells will prepare accounts showing
no overall profit. To make an overall (taxable) profit on renting out a plane, you need to rent it out for somewhere of the order of 100-300 hours/year. The only way you will achieve that many hours would be by pretty care-free marketing (which will trash it pretty fast), or by leasing it to a school (which will trash it even faster)
The question is whether you can be bothered setting up your activity as a business, via a limited company. I wouldn't bother. Far better to find somebody you can trust and let them buy a share, and share all the costs, in the usual way.
People have often set up limited companies and VAT registered them, so they could reclaim the purchase VAT on the aircraft. For any reasonably decent plane, this is a massive amount of money recovered e.g. £35,000 on a new TB20. But it was a stupid approach, because all renters (including you the owner) then need to be invoiced at the rate "plus VAT" and this continues for ever... so the initial saving was an illusion. A much better way was to purchase the plane via Denmark, zero VAT, but this option ends 31st Dec 2009 so I guess more people will be going back to the VAT reg'd company route... but aviation business is tough and so many renters cause trouble.