The answer to this question is yes, if there are grounds to do so.
Whilst someone’s wishes upon their death are of paramount importance, the courts do consider the needs of others known to the deceased who may be disappointed by the contents of the will.  It may therefore be possible to make a claim for financial provision from the estate of the deceased.
In addition to this, there may be concerns as to the contents or the circumstances surrounding the making of the will, which invalidates it.