Elizabeth Hollingsworth died on 15 Feb 1768 and as far as I can see, Thomas then married Rosamund Smith: "'Thomas Hollingsworth of this parish widower and Rosamund Smith of St Stephen Coleman Street, spinster, were married in this church by license this 3rd day of May 1768" St Giles Cripplegate. (His first wife had been Margaret Smith, so possibly these two ladies were related?) Jemima, my 6x great-grandmother, was significantly also married in St Stephen's Coleman Street.
That seems very soon afterwards, but I guess the haste may be partly attributed to Thomas needing a step mother asap for his young twins, who had only been born (or at least christened) the previous November. Rosamund Hollingsworth's will refers to her husband, Thomas 'of Moorgate', by then being buried at Bunhill Fields just outside the old city, and also to John Hewett - the son of Jemima. This all seems to fit together, as far as I can see.
I'm certainly not claiming to be totally 'right' and do please double check things. I've uncovered more details since putting the original post on here and Rosamund's will especially appears to confirm this web of relationships and sequence of events.
(Incidentally, it appears to be from the Hollingsworths who moved off to Birmingham, and kept the family tradition of being butchers, that Howard Hollingsworth eventually emerged. He was the joint founder of Bourne and Hollingsworth's department store in Oxford Street; and his sister, Clara, married Walter Bourne....... but that, as they say, is another story!)