Reminds me of the time when most cars carried a spare set of spark plugs under the bonnet.
Will the plug carrier allow the fitment of extended nose plugs i.e. N9Y ?
On my modern you have to part dismantle the engine to get at the spark plugs - but there again I have never had need to remove the spark plugs - they just seem to go on and on without fault unlike the Minor which had the plugs replaced at 12,000 mile service intervals or every year.
With modern plugs the electrodes do not seem to degrade as quickly as they used to in the 50s, 60s & 70s.