I couldn't find out from service records when the spark plugs had been changed or if they ever had been changed (48k miles 55 plate).
Decided after 3 months ownership I should change them although no problems with fault codes or misfires. Purchased 8 of the correct NGKs. Old plugs removed, front set Denso, rear set NGK, all a nice colour but very worn down centre electrodes making for a large gap. All the plugs looked very old, could they be original?
I understand Honda often used both NGK and Denso on the same car on the factory floor.
New plugs fitted and maybe the placebo effect but engine feels smoother and sounds sweeter and appears to pull better at low revs.