If you look on the beck of your card, you should find a +44 number for calling from abroad. It might be in very text, but is usually on the reverse, somewhere below the signature strip.
When calling, bear in mind UK working hours. Better chance of getting through early their time.
Don't know if you are aware, but there is a Lloyds Banking app for your phone.
It has facilities for transactions, managing your card, such as freezing it, or changing your PIN, report lost or stolen.
Also managing a transaction and other support or contacting support.
HTH