There is no central place where Wills have to be registered. Many people hold a photocopy of their Will and this will usually be in an envelope that states the location of the original. If you can’t find any evidence of a Will but you are confident the person who died wrote one, telephone local solicitors to ask if they hold it. Some people store their Will in a bank safe deposit box so that is also somewhere to make enquiries.
There are also commercial companies who have set up Will registers that you can find on the internet but you will have to pay a charge for them to search. If a recent Will cannot be found at all and an older Will is found, the older Will has to be used even if you feel it is no longer what the person who died wanted.
If you cannot find a Will, it will be assumed by the Probate Registry that either none was written or that it had been destroyed because the person had changed their minds. Therefore the Rules of Intestacy will apply. You can find these here.