wouldn't difficult starting indicate an air leak? Perished crank seals perhaps? If its only done 5800 miles over its whole lifetime it may have been sat in storage for a long time which would've upset the crank seals. Including the centre one.

If the other suggestions don't yeild results you should put together a leak down testing kit to check for air leaks.

If you do a forum search you'll be able to find photos and details of the kit i made up for testing my engine.
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