The flywheel has marks for T3 and T4 but you dont need them for installing the camshafts.

Hi Neophist / Seven Three Seven

No, not to worry "seven three seven" You didn't cause any confusion for me and I can confirm that all 4 cylinder timing marks are on the flywheel and not just 1 and 2.
I have now I think, located everything properly using the very helpful advice received from you both. Thank you.

As it turns out (no pun intended) I hadn't got any parts in the wrong place but the piston and cam/cam holder markers positioning as you suggested wasn't quite right. This was further compounded by the cam idler teeth (I think that is what they are called) not matching with the gear cam below until the cam holder bolts on the dowel pins are loosely tightened. Then all suddenly came right.
I hope this all makes sense.

So now to check. I have just got to tighten down all bolts with the torque settings and then do a few full turns of the crank as you both suggested to check for correct cam rotation order, ie firing and exhaust strokes match with the crank piston cycle.
But all looks sensibly placed and set to move logically. I will post back the results.
Just one question in the mean time please. The valve clearance settings ! Do you know what they should be?

Many thanks again for your help.

Sounds good so far.

I trust you're using engine assembly lube in the camshaft journals during assembly (as Honda recommends). Also, a technique for getting the idler portion of the gear-drive set properly is to use a black marker to color a pair of the teeth, this will show you whether or not they are correct (again, this is how Honda recommends doing it).

Yes all lubed accordingly.
I have now tightened and turned and checked all the sequencing a few times and all appears to be good.

Just the valve clearance settings to get now. I will check with the local Honda dealer. If no luck there, I will raise a separate post to ask.

Thanks again for all the help.

valves clearance:

Inlet: .11-15 - optimal .13

Exhaust: .18-22 - optimal .20

Brilliant.
I'm all done and ready to go. Will test run asap. Thank you so much.