Overheating, Flush Radiator?

I've tried to do a bit of research before posting this on a few different sites but lve just confused myself.

My daytona 650 has started over heating, of course it has just as I've had the springs uprated!

Here is what is happening
- It gets hot within minutes even just ticking over.
- both the big radiator hoses get warm.
- fan kicks in at about 104 but doesn't cool the engine, temp keeps rising.
- temp hits over 120c when slow moving or in traffic.
-coolant is between min/max when bike is sat upright.

My plan tomorrow is to take the front fairing off, undo one of the hoses to drain the coolant, figure out where the thermostat is and and remove, test in a bowl of bowling water.
I think this is the right way to go from what ive read but here is where I am really confused,

1- do I just put hose and thermostat back and top up coolant or do I flush the system?
2- flush the system and if so how as I've read in one post to stick the garden hose in one end and flush it out then top up but this doesn't sound right.
3- take radiator off?

4- I'm not sure where to get bike anti freeze from, I do have a halfords, local if that's any good, I've read about Oat, hoat, ready mix but not a clue so a link to the best one would be great aswell as this engine runs hot I'd rather use the one with best cooling properties.


Sorry its such a long post but I wanted to give as much information as possible so if anyone has a step by step guide or even just things I've missed to do that would be much appreciated.

 

I've just had to look through and I have seen my fail ‍♂️
No editing will be done

 

Quick update - Just took the thermostat out of the bike, put it in a pan of water and boiled it, it opened fine, I've just let the bike tick over without the thermostat in and it slowly climbed to 103 and fan kicked in, it continued to rise to 107 and started cooling which it hadn't done over the last few rides, just to make sure, I held revs at 3000 until temp went back upto 108 it went upto 113 and then started dropping again.

That suggests a faulty thermostat as that and the fairing are the only things been taken off, but the thermostat opened fine in the pan of boiling water

So a thermostat will be on order unless anyone can tell me its better to check something else first?


One thing I did notice is that the liquid was pretty clear so I'm guessing it's 100% water so that's going to get replaced with coolant.