Check Engine LIght?

Recovery guys had to hook up, deflood then start motor , continuously scranking the engine. eventually started. Failed MOT on minor things but cat readings were erratic then eventually passed. Engine managment light did come on once Changed over starter motor as theother one was burning out. Engine management light went out
The car now is sluggish to start - i suspect again the starter as it was second hand.
The car doesnt start after a run and engine gets very hot.The other day stopped to fll up at petrol station and when tried to start again , cranked over but no firing up. The fuel had indicator was below zero, and DSP light was on and Oil pressure was at zero when ignition on. Ten minuites later tried cranking and it hesitantly started, fuel went to half full and oil pressure just above mid point. On the drive back home a sweet smell but nothing too major
Could this be engine temperature sensor is faulty or cat converter is faulty? or could it be anyting else like coil and leads? Advice would be appreciated. By the way - acceleration is good, just been serviced and UK car
thanks