Rene, it's a long way from perfect, but with a little work...
Scott, I hadn't really considered that, thank you for the link, in fact I think the rear pump with the straight connectors has 1/8" NPT threaded connectors, I just looked the spec's up on Wiki and it seems that way. I will measure in the morning. That would be a good fix for that aspect of the snag.
I just got home a few minutes ago, according to the car thermometer it's -2ÂșC outside so I thought it prudent to drain the Marlin. I haven't added antifreeze yet... It's very cold with a clear sky so the temp could drop quite a bit further by dawn. No point in risking my newly built engine and repaired radiator.
Looking forward to fixing the bonnet hinge in the morning.