Your monthlies are then £10800, plus the proportion of the per-hour cost which at a guess is maybe £30/hour - correct? How many hours does the plane do per year?
We do around 170 hours on average and the finances have worked out fine with a reasonably healthy positive balance although maintenance costs have been reasonable we accept they are likely to increase. This also covers Garmin, charts updates, dingy service, plus we pay $750 USD to
www.savvymx.com who have saved us a large ammount on maintenance costs and can arrange Pre Buys in the USA very competent pre buys in the USA.