81 ‘Uncle Dick’ was Richard Lewis (b. 1861), one of Albert Lewis’s four brothers and two sisters. See The Lewis Family in the Biographical Appendix.
At the time this letter was written, Jack and Warnie seem never to have met Richard Lewis nor any of his family. ‘Sandycroft’ was the home of C.S. Lewis’s great-grandfather, Joseph Lewis (1803–90), in Saltney, Flintshire. Richard and his daughter Eileen were going to visit members of the Lewis family still living there.