All done, boxed up ready to send.
It was pretty straightforward and simple though the process on my Galaxy Note 4 did differ slightly from the "howto" I linked earlier.
Where it differed follows:
Part 1: Encrypting Your Data:
step 2: The phone didn't need to be fully charged, out of curiosity, with the phone charging I attempted to start the process with only 67% of battery charge, the phone complained it required at least 80% so I charged it to 87% and tried again, the encryption process began.
steps 4 & 5: I've always had a 4 digit 'pin number' to secure access to my phone so I was expecting I'd need a new 6 character password at this stage. Wrong, it asked for the pin number and off it went.
Interestingly there was an added option in step 5, an option to include "memory" where no data was written (or words to that effect). I presumed by "memory" it meant free space on whatever type of drive is installed, i.e. where the data is stored, and assumed that with the potential for previously deleted data to potentially reside there I chose to include that.
step 6: 15 minutes is all it took and afaict it only restarted once, twice if you include when it finished and reloaded android.
At this point my phone was HOT, by far the hottest I have ever experienced it... not hot in that you can't touch it but certainly hot enough that I'd be seriously worried if I was using it under normal circumstances!
step 7: Again, my normal 4 digit pin sufficed.
Part 2 Formatting the SD Card: Not used as I'd already removed the Sim & SD Cards.
Part 3 Wiping the Phone: As described although I did have to "factory reset" twice... I don't know why but the phone did some very odd things after the first reset including restarting , I suspect it was possibly crashing due to overheating because I went straight from encrypting to resetting without letting it cool down, so I shut it down and waited 5 minutes before running another factory reset.
Part 4 Taking Extra Precautions: I skipped this for reasons I explained in a an earlier post.
In summary, it was painless, now I just have to sit back and wait to see if the company that quoted me £134 for a device in "good" condition honours their quote. I'd be amazed if they don't given they have a 5 star rating on trust pilot and I'd be happy if someone sold me the phone and listed it as in mint condition:
https://uk.trustpilot.com/review/www.musicmagpie.co.uk