Engine out full rebuild approx 5000 miles. All good.
Coolant level generally stable with usual top ups / spit out excess.
After no idea how long noticed rad cap upper seal was missing.
Replaced cap with new…
… now coolant loss…
Not via rad cap (no streaks / tell tales).
No tell tale of head gasket leak in oil cap / on dip stick.
Checked hoses (limited to those accessible from front / above.)
Noticed crescent of rust sat on the upper lip of the hose where vertical larger diameter hose connects to water pump, a few shiny sticky streaks running down the hose.
Volume of loss is around 3 pints after 200 miles.
Have yet to test after tightening but would a tiny ‘pee’ leak drop such a volume – as I write, answered my own question; of course it could…
Checked again better light this morning, found wet rusty sludge from central core plug….
Sure I’ve read of a sealing core plug design with tightening bolt – comments please.