Coolant refresh - advice appreciated

After years of being away from the forum with relatively hassle free driving, I'm back for some more of the good advice I've received before.

I normally only do short drives these days, nothing over 20 mins. Recently, on stopping at a toll plaza on the motorway, my '09 1.8TDCI just completely cut out. No warning lights. Eventually got it started again and uneventful driving until stopped at off-ramp near home. Same thing again. 

This time a cop pulled in behind me. Suggested it might be overheating, but temp gauge read the usual 90. Got her going again and made it home. 

That was about 2 weeks ago.

On looking at the coolant, it actually is nothing like the pink it's supposed to be, rather like it's contaminated with rust.  Plus there's something that looks like a clear(ish) crystalline deposit on the inside of the coolant reservoir tank.

Did a check with a Bluetooth obdii scanner today (didn't have FORScan available - left laptop in work). It showed an error about low fuel pressure but there's been nothing with it since, although no long drives either.

It then occurred to me that I don't hear the fan spinning down when I turn it off anymore. My thinking is that the short drives aren't causing the thermostat to be opened much, if ever, and maybe the overheating is real and the low pressure is a coincidental finding.

Finally, on squeezing some of the larger coolant pipes, there's a crunchy feeling in places, so I'm thinking that could be a scaly buildup. 

tl,dr: coolant is filthy, might be overheating.

So the plan is to refresh the coolant, thermostat and reservoir:

1) drain it down and rinse with clean water until it runs clear ( including a reverse rinse on the rad if I can manage it)

2) fit a new thermostat and put in clean water and a flush (Prestone) and idle it for 20-30 mins

3) drain it again and re-rinse until clear.

4) fit a new reservoir and fill the system up with coolant and top up as needed after first few runs.

I'd appreciate any advice on this. Have I missed something obvious? Any tips on how to do it right / what not to do. All advice greatly appreciated.

Thanks for your time

Sco