The following text is from the original listed building designation:
1. 5275 KING STREET (South-West Side)
No 60 TR 3357 NW 2/291
II GV
2. This was formerly the Methodist Church. C17. It is a building which was transformed about the middle of the C19 and consists of a solid wall and parapet, 2 bay windows 1st floor and 2 fixed lights forming lst and 2nd floors. Gothick headed glass in shop window and pair of doors in the centre. John Wesley preached at this place when he visited Sandwich.
Nos 60 to 68 (even) King Street form a group.
Listing NGR: TR3314358010

Was it a church? There is a church shown on the 2nd-4th Ed OS 25m to the NW of ths property (now demolished).

English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.