Did you try the forgot password ***** yahoo. then you have to answer some security questions so that they can verify that it is your account. then they will either send you the password ***** your cell phone that you set up with them or if you set up a 2nd email with them they will send it to that account.
It looks like the support page for yahoo.co.uk account are under maintenance right now so you can not go that way until the support page is back up.
when you go to your yahoo page, click on sign in, then click on I can't access my account. then choose forgot my password. then input your user id and they might have a code there that you will have to type in. hopefully you will have registered a 2nd email account with them so input that then click ok or send. they will send the new reset password ***** that 2nd email or it will ask you do you want a text to your phone (if you have set it up) and they will send you a text. The easiest way is just to answer the security questions you typed when you first opened your account.
Here is also a link that can walk you through everything above that I posted: https://help.yahoo.com/kb/yahoo-account/SLN2081.html?impressions=true
Since you are in Ireland you might be able to reach their customer service at: 08719090581For the US it is(###) ###-####.Those are the numbers that I have found.
The response was swift and correct. I would definately recommend to others and I will certainly go this route again with future queries, thank you.