OK...well to answer my own questions after all that worry & procrastination the solution to me was as follows using the info from this very website;
1. Install rbfeeder by typing;
sudo bash -c "$(wget -O -
http://apt.rb24.com/inst_rbfeeder.sh)"
2. After the package had installed I typed;
rbfeeder --set-network-mode off --no-start
3. I then installed the compiled 32-bit MLAT package from Ingo abcd567 by typing;
wget
https://github.com/abcd567a/mlat-client-package/releases/download/v1/mlat-client_0.2.11_BUSTER_armhf.debsudo dpkg -i mlat-client_0.2.11_BUSTER_armhf.deb
4. After it had downloaded it left me at a command prompt ready to just hit <return> to install
5. I then rebooted, plugged in the FlightStick and connected the antenna
6. When the system was up I used RDP/SSH to login remotely to the system as it is headless and typed;
rbfeeder --showkey
7. Going here
https://www.radarbox.com/raspberry-pi/claim and using cut & paste I pasted in my sharing key that was shown at Step 6 above
8. I was taken to a page where I input my coordinates, selected exact and show to confirm my location and input my antenna height and BOOM! I was taken to my RadarBox Station page!
At first the MLAT was inactive in red and clicking the green instruction link it told me to do what I had already done with regard to coordinates & antenna height but after a few minutes it came up as MLAT active (230 stations synced) and I was in business!
Coincidentally my Max Range is 230NM...must be my lucky number! :)
And all that worry for nothing. Mind you I was the same when I purchased my first Raspberry Pi to run Pi-hole and it took me a year to actually get round to taking the plunge...
Hope that helps somebody else who might be as nervous as I was...
I guess the only questions I might have left after the dust has settled might be;
1. How to listen to the VHF FlightStick bearing in mind I am in the UK?
2. How to setup a feed to FR24 and possibly others in the future?
3. How to keep the integral dump1090 and indeed everything else updated to the latest versions?
Thanks & kind regards,
-=Glyn=-