No that's not right, they are no balls of fire, but much better than this.
When was the fuel filter last changed ?, when was the water last drained from the filter head ?, are you sure it's getting full movement at the pump from the throttle ?
If as I suspect it is a lucas cav pump these can be turned up, fuel supply wise, my old 1.8d escort mk4 would eventually get to 112 mph on the clock, after tweaking, also try some millers diesel fuel treatment in it, but double the dose it says on the bottle, it's magical stuff and works wonders, as does using bio diesel every now and again if you can find it.
Very unlikely but also check your air filter is not blocked.
tabetha