I have the Haynes manual that covers CVH engines - bought when I had a 92. 4/4.
It details how to change/dismantle a d rebuild oil pump.
Haynes show it done with engine out so I don't know how easy it is in a Morgan withe the engine in situ.
A couple of points include........
Remove timing belt/ sprockets/sump.
If just replacing the gasket then refurb of pump itself may not be needed but a new oil seal for the pump housing is recommended.
Pump should be primed before refit.
Refitting the sump involves using sealing compound at both ends - pump end and rear.
The procedure is obviously for the Escort/Orion's the engine was mainly used in so an in-line set up may lead to differences in access etc for a Morgan.
I can't remember enough about it as I didn't need to do any such work.
Vaguely, it is possible it will be straight forward with a car high up enough off ground for access, BUT.... Morgans have in line gearbox (Ford type 9 usually) so there MAY be bell housing set up differences to deal with.
Best bet is to see if someone here has replaced a sump on a CVH to see if any complications were found.
At face value it should be do-able at home with good axle stands though.
If you want the Haynes manual then PM me. You have first refusal if anyone else wants it.
sospan