What does 1994 refer to. Is it the year of death, year the Will was written, year of execution?.
What does Nicola receive?. Something substantial such as money or a personal item, a memento?
How does this compare with what other beneficiaries receive?. What age is the deceased person, godparent of Nicola?
Looking forward to an answer to these questions from OP.
Could a solicitor contact the GP surgery[ies] close to last known address, including a letter to be sent on to Nicola? GPs records will have NHS number and maybe NI number, through which a current [British] location and address can be found [not by ordinary mortals]. This happened to a friend who had lost touch with his family; when his father died 20 years later and left him a legacy, a solicitor wrote to mother/father's GP who was able to contact authorities - who located friend through NI & NHS numbers - and the letter was sent on by [I think] DWP o rmay have been sent to current GP. He received the letter within a few weeks.
If Nicola has moved abroad - even more difficult!