There is scope for further academic study post registration, this is what truly increases employability and furthers your career.
No. Any course which is labelled as pre registration nursing - whether it be BSc/BN or MSc, leads to registration with the NMC and being able to practice as a nurse. If you don't have a degree, do the undergrad. If you do already have a degree, either do the undergrad nursing in 3 years or postgrad in 2 - but bear in mind that, when you qualify, you'll start at the bottom of band 5 whichever one you do.
What i want to know is that I can do a masters after i’ve done my undergraduate?
If you mean do a pre-registration masters in nursing after a different degree, yes.
If you mean do a masters after a nursing degree, yes, however it's more common to get a bit of experience in practice before choosing which route to go down for a masters.