If all is as scheduled and no parts need extra work or replacing:
Annual items £3-4k
100Hr Items £1.7-2k
50Hr £1k
I had a well cared for aircraft from new, always hangared, and a number of unscheduled items each year over my ownership (aux fuel pump, aux fuel pump, hydraulic servos, pitch links, crankcase seals, sprag clutch, oh yeah.... aux fuel pump
) which varied between £1-7k each to replace.
Ownership can be fun but not generally economically worthwhile especially at 50hrs/year. Start a syndicate - the schools don't like them particularly as it eats away at their SFH clients and profits, but as an owner it makes far more sense...