Interesting snippet I just spotted while trawling appeals policies for a major update of the Immigration Act 2014 ebook and course:
A person who has an appeal pending can make a fresh application for entry clearance in the same or any other category. There is no requirement for a person to withdraw an appeal.
Comes from section 20 of Appeal procedures: APL01. I’d always have said this was the law but thought that ECOs nevertheless refused to process new applications while there was an outstanding appeal.
Different provisions apply within the UK: it is not possible to make a new application within the UK while an appeal remains outstanding owing to the operation of section 3C of the Immigration Act 1971 and the case of JH (Zimbabwe)  EWCA Civ 78.