It will need a proper repair in due course but it's running well apart from the leak so I don't want to disturb too much before I do the Giro SW in September. After that I can take the head off.
As for it reading a bit dodgy! I too thought it a bit sus, but as my ex-Merchant Navy friend recommended Tolley's, as an indispensible part of the engine room toolkit at sea, I thought "Why not?". Wouldn't be without it now, as it works on those annoying wee water leaks as well.
Good health, BillR