It appears Thomas Symons was a surgeon, and Pepys didn't like him because he had exploited family connections during the Interregnum to make some ill-gotten financial gains.
A details analysis, gleaned from at least two entries in L&M, is at
https://www.pepysdiary.com/diary/1660/06/27/#c5670
References
Chart showing the number of references in each month of the diary’s entries.
It appears Thomas Symons was a surgeon, and Pepys didn't like him because he had exploited family connections during the Interregnum to make some ill-gotten financial gains. A details analysis, gleaned from at least two entries in L&M, is at https://www.pepysdiary.com/diary/1660/06/27/#c5670