Have a Royce sq taper bb but need to know wether correct length for my 2010 Helius CC, anyone know the correct length required?

It will depend more on your chainset. What you using?

My helius am had a 73mm bb

middleburn chainset RS7

From middleburns web:
Having the right BB length is crucial to having gears that work as well as intended.

Middleburn cranks run a 50mm chain line.

For a standard MTB setup a 113mm axle is needed for ISIS or square taper.

However, there are far too many variables to always be able to predict what bottom bracket you need. BB-mount (“E-type”) front derailleur and chain devices can throw a stick in the works, as can a lot of oddly designed frames.

If in doubt have your local bike shop fit your cranks.

So 73/113??? If you already have the bb, why not try it and see?

Thanks