It's a good idea to keep your Will up-to-date, especially if there has been a significant change in your personal circumstances like the ending of a relationship. People may also forget about funds where a beneficiary can be nominated, such as a pension. 

While an application to the court under the Inheritance (Provision for Family and Dependants) Act 1975 may be possible, it's not quick and it's not cheap. Just remember Illot v Mitson in the Supreme Court last year, or Jarndyce v Jarndyce where the only winners were the lawyers...