Opinions will invariably differ; yet, as subjective viewpoints, none can be deemed right or incorrect, as it ultimately depends on one's perspective.
When discussing a car that is well-maintained and has no intention of modifications, with an annual mileage slightly exceeding 3,000 miles, minimal faults arise, normal wear and tear is disregarded, and advisories noted during MOTs are addressed, I maintain that investing in the upkeep of that exquisite Mercedes-Benz is my perspective; however, I fully acknowledge your viewpoint, despite my disagreement.
In my opinion, the expenditure of Β£16,000 since 2008 is more than sufficient.