[carlos_dfc]

Hi

At the times that most people in UK will look at the sky (7pm until about 11pm)
Castor and Pollux are positioned to the left of Mars.
Can't miss Mars - very bright, and orangey, to the east (climbing higher as the night goes on)

Also - unfortunately, you can't see all 6 elements in the Castor system.
If you look with a telescope, at high-ish magnification, you'll see that Castor appears to be a very tight double star (only 3 arcseconds separation)
Both of the elements you see are themselves VERY tight doubles - so close together that a telescope can't separate them, a sectroscope is required to detect that they are doubles.
Then, a little below Castor, is a dimmer star, at just over 1 arcminute away (70 arcsec) This is also a spectroscopic bimary, and is gravitationally bound to the other Castor stars.

note:
There's another star, 3 arcmins to the right of Castor - it is unrelated to the Castor system, and is simply coincidentally quite close to our line-of-sight.

I often advise astronomy beginners to use Castor as a test of their telescope's optics.
A very good telescope will be able to 'just' separate the two brightest elements at around 50x - whereas a poor scope will require 150x and higher - a bad scope won't be able to separate them.