from what i know, dublin is the easiest to get first class honours. Royal Holloway is part of the Russell Group unis in UK so they have some status.
why PSB? why not consider the other options too? if your diploma is not recognized then go do a proper part time diploma from polytechnic.
https://www.sp.edu.sg/pace/courses/...ecialist-diploma-in-cyber-security-management
at the same time you can do standalone certs like these. it will look good on your CV.
https://www.ntuclearninghub.com/cyber-security-courses-boost-career/
https://www.smu.edu.sg/programmes/p...ducation/future-work-cyber-security-awareness
after that you can apply to the proper unis.
https://www.simge.edu.sg/programmes/programme-listing/?discipline=it-computer-science
don't look for the easy way out. you only go to private uni if your current or future employer guarantees you in writing that they will recongnise your cert and increase your salary or pay you accordingly.
take a look at these first before you jump about northumbria.
https://sipmm.edu.sg/courses/
https://www.simm.org.sg/LSC/DLSCM.asp
yes nothumbria is a UK uni and unless you are going to work for big companies where the HR even heard of northumbria then don't bother getting degree from them.