Hostels in Ireland and UK

Hi everyone! I’m going on a trip with 1 other traveler at the end of this november and am looking for some hostel suggestions.

Preferably within walking distance of pubs, shops, etc; somewhere in the center of these cities! Would also appreciate suggestions for hostels with private rooms, but shared spaces such as bathrooms are fine! And of course that are safe and clean:)

Dublin, London, Portsmouth, and Edinburgh. Any input it appreciated! Thanks(: