Wow! - thank you all very much for the replies!!! Legends!

With all your help it worked!

The main breakthrough was:
@ETFbitcoin uname -a worked perfectly and let me know it was a 64-bit set-up. Which gave me the confidence to follow @odolvlobo advice regards the alternative file name for the download, you were spot on with recommending aarch64-linux-gnu.tar.gz

Thanks everybody! ...just 11 years of sync to go 
stw

Hi Guys, Hopefully you can help!

I've downloaded bitcoin-24.0-x86_64-linux-gnu.tar.gz

From bitcoincore.org/bin/bitcoin-core-24.0/

Carefully followed the instructions for Linux on the Bitcoincore & Bitcoinorg webpages.  Run the security checks and all the way to the end, passed sudo install stage. Just can't seam to get the bitcoin-qt to work to start off the magic and run Bitcoin core GUI.

Error message:
bitcoin-qt: cannot execute binary file: Exec format error

I'm wondering if the original download is wrong?

Kit: Rapsberry Pi 4 (8GB Ram), running Ubuntu latest version with an external ssd ready to go.

Any ideas would be a massive help... I'm in a google / youtube tutorial doom spiral

stw