WARNING Some versions of Teckin SP23 come without power monitoring and do not use ESP8266. Those cannot be flashed with Tasmota.
The Teckin SP23 appears to be a clone of the BlitzWolf SHP2 hardware with Tuya software / firmware.
The uses an ESP8266EX and is capable of switching up to 16 amps at 250 VAC.
2 Teckin SP23s (marked V1.2) bought from Amazon UK in January 2019 have been flashed successfully and use BlitzWolf SHP2 Sonoff configuration. Voltage calibration may be required for accurate power monitoring. Confirm flashing a box of 4 purchased yesterday (09/11/19), from Amazon UK, with Tasmota 18.104.22.168, using tuya-convert v2.2.0. No version number visible on the plugs. New SP23s (without power monitoring) bought from Amazon UK (14/02/20) unable to be flashed. Again, no version number visible on the plugs.
Serial Flash Instructions
No hardware preparation is required to flash if you are confident about having the same version and can easily be flashed following the procedure detailed at here using https://github.com/SynAckFin/TuyOTA
Flashing over serial guide by Marcus Bennett:
How to disassemble if desired:
If you wish to confirm you have the same hardware the Teckin SP23 can be opened by hitting each side of the plug at the lip with a rubber mallet or similar. This will leave a visually unblemished enclosure which can be resecured with superglue or similar.
Disassembled device pictures: