If that Rover motor was the K Series, whoever put the plastic Thermostat Housing behind the water pump was sponsored by the Guild of Gymnastic Mechanics. Especially when the engine is fitted to an MGTF. Those who have ever had complete coolant loss when the housing splits know what a hidden bastard it is to get access. And don't get me on Alternator belt adjustment for this vehicle, that's another simple job (not) done on the ramp or like most of us, lying on your back in the dirt.
As for berg's leak, core plugs, a weeping hose or that failing pipe fixed with JB Weld or Epoxy putty for now rather than a complete tear down leaves more drinking time. Make sure it is actually coolant leaking, (life endangering taste test) not condensate from the Air Con......
Swarfy