Remove the engine or not advice

About 6 months ago I did an engine out job at home with a Ferrari mechanic. Obviously he ripped me off becuase when the engine went in I have had these minor on and off issues. I wrote a thread about the Aussie mechanics ripping us off down here.

So at this point in time I have a coolant leak coming from the thermostat housing and the heat exchanger. The coolant is a slow leak but over the last 6 months it is all over the belts at the front of the engine, on the speedo sensors and crank sensors.

I know you can change the thermostat gasket with engine in and can change the belts as well except the cam belts.

The question is do I drop the engine again to clean the front of the engine and fix this leak up or try and do with engine in.

What would you do??