The way to spell St Laurence’s or St Lawrence’s has been a point of contention for many centuries. For instance, this is a reproduction of an article first published in the Parish Magazine of January 1894 : –
“The Editor has been at some pains to discover the proper way of spelling the name of the Saint after whom our church is called. He finds that although it is often spelt with a ‘w’, the correct spelling must be with a ‘u’, not ‘w’. St. Laurence was a deacon of the Church of Rome, and suffered martyrdom there, A.D. 258. There is no such letter in the Latin alphabet as ‘w’. Archbishop Laurentius, who came over with St. Augustine, and succeeded him in the See of Canterbury, came also from Rome, and in the list of Archbishops his name also is spelt in the same manner, doubtless for the same reason.”