I agree with CASE. The main relay is Honda's typical problem for late 80's and early 90's models. Rover is actually a guise of Acura Integra.
It is not difficult to diagnose main relay problem. When in normal condition, if you turn key on but keep engine off, i.e. not crank the engine, you should hear your fuel pump working for about 2 seconds. At the same time, you can see a check engine light or PGM-FI light on the dash board turns on for 2 seconds and then turns off itself. If can not observe both, you should suspect the main relay.
The main relay locates on left side of driver kick panel, beside the driver door. Touch it with left hand. You should feel it vibrates once when you turn key on with right hand. Otherwise, the main relay is faulty.
You can also use a multimeter to check power of all terminals of the relay. Remember which terminal has 2 second power supply when the key is turned on. When the problem occurs again, check this terminal again. It it has no power anymore when turning the key on. It must be the cause.
You can drive to a junk yard, take off the relay and bring it with you. Find a Handa car to match a main relay with the same component type, shape and terminal numbers. A used part should be not more than $20. Ask a Honda dealer first, new part could be cheap too, because old model cars are phasing out.