Runs Hot and Checking Oil

What year is the vehicle ? The cooling fan relays have nothing to do with the temp. gauge . GM had problems with the stepper motors inside the instrument cluster . Hooking up a professional scan tool to check what the PCM - engine computer is seeing from the engine temp sensor . You have duel cooling fans controlled by three relays . Checking to see what the actual engine temp. would be the first step , checking to see if the scan tool can control the cooling fans .
Look on youtube at videos on gm instrument cluster stepper motor problems

Heater core is not working.

How many fans do you have under your hood in front the of the engine between the engine and the front grill ? Sound like you may have two problems an oil leak and a over heating problem. first check the cooling fan or fans and make sure they are working. Second check the valve covers to see if they are leaking oil onto the engine or exhaust.

You should make sure there is no air in the cooling system-from a cold start, let it idle until the radiator fan kicks on with the surge tank cap off-make sure the tank is fully up to level at this point, that should eliminate air in the system as a cause. If you do not have a scanner that gives live readings, get one so you can monitor the engine temp-a factory gauge is not overly accurate. Your temp when warmed up, air off should go to about 212-215 and the radiator fan should then kick on-temp should drop to about 200 and the fan should shut off-this is normal.

is the water pump, belt and tensioner OK? its not where you think it is. its on the drivers side of the front cylinder head.

a late opener will make it run cooler as it cools the radiator for longer

your engine is probaly over heating you will  need to go to the nearest auto mart and get engine cool off.

That is quite normal - these bikes run very hot and will typically reach temp where fan kicks in (103 deg C) while bike is sitting at idle, even if not particularly hot weather. Needs good airflow through the rad to keep the temp down. 
Fortunately, when fan comes on it lowers the temp quite quickly. 

sounds like the radiator is blocked replace it or have it cleaned at a radiator shop

Hi,
This sounds normal to me..... Except "runs to hot when idling"

When you're driving about (airflow over rad) all seems fine, but when sat in traffic idling - the fans come on to cool. Is the problem that even with the fans running, temperature still goes up - and fans never turn off again?

Is this the problem?

If it is, then the coolant pump may be badly corroded, not driving efficiently, or the coolant needs flushing and replacing.