I did a little work on that line up around the 15th century. It's very messy and gets into a tangled Nest. I really suspect there were two of Christian(a) Warcup, possibly aunt and niece - the dates were just crazy otherwise.
There's a list of Lord Mayors of London here: http://en.wikipedia.org/wiki/List_of_Lord_Mayors_of_London
No Lockes. No Wilkersons. Sir Ralph Warren Sir Ralph Warren, Lord Mayor of London is on it twice - he's right in the middle of that Nest.