Bottom bracket length and spindle diameter

Trying to educate myself more around bottom brackets, as I'd like to change my crankset.

I currently have this bottom bracket installed, in a length of 110.5mm: https://www.vpcomponents.com/vp-bc73

Based on this, I've been able to work out that I need an English Threaded, 68mm BB. Based on the crank I want, I know it needs to be compatible with 24mm spindle diameter.

How do I find info about lengths and compatible diameters? Googling about, it sounds like a Hollowtech 2 BB would be compatible with the spindle, I can't find any info about the length?

I was thinking about getting this one - but really I'd like to know how to find the info and make the decision myself

https://www.halfords.com/cycling/bike-parts/gears-drivetrain-and-cables/shimano-tiagra-bb-rs501-bottom-bracket-english-threaded-cups-797486.html?cm_mmc=Google+PLA-_-Cycling%3EBike+Parts%3EGears,+Drivetrain+and+Cables-_-Cycling%3EBike+Parts%3EGears,+Drivetrain+&+Cables-_-797486=