Thanks for that.
The car has done 45,000 miles, the service book shows the plugs were changed around 35,000 miles but I am a bit suspicious about this as it was not done at the Nissan dealers and I would have thought any garage doing the job would have changed those hose clips, something I will certainly be doing.
I could check the two spark plugs that can be got at without dismantling anything but it would be easy for a garage to change those two and leave the other two.
If all the pipes I need to disconnect are simply for air then the job is fairly straightforward (providing no bolts are dropped) what threw me was the Hayes workshop manual stating that one of these hoses contained radiator fluid hence the need to drain the system.
Post pictures of your Juke here