If you plan on keeping the zed for the long term I'd say go ahead.
I've probably lost near £24k on my zed if I sold it today, but looking back wouldn't have changed my decision.
Paid £30k back in 05 for my zed but after 13 years the depreciation has slowed right down. I took a big hit originally but have had a car without any bad surprises due to unknown history that brings a smile to my face daily.
If I was planning on changing after a couple of years I'd probably go 2nd hand rather than finance a new one, as a £20k hit in 3 yrs sounds much worse than my £24k in 13!
At the end of the day, different strokes for different blokes.
I know people that'd happily spend thousands every year on holidays but would consider buying a new car bonkers as you lose on depreciation and vice versa.