We do not have a kit to showcase this. However, both the 4700S and 4200L are equipped with most of the standard communication protocols such as UART, I2C, and SPI. These can be used to communicate between the two devices and you can send the inductive sensing data (the sensor values and additional data such as the difference counts) to the host device using any of the standard protocols.
There are several code examples available to showcase the communication such as I2C master slave (CE222306), SPI master slave (CE224339) etc.
How about ISP programming of the 4700S from the 4200L?
i.e. we have the cypress standard bootloader so we can update the psoc 4 via USB,
but we need a way to also update the 4700S via I2C or UART (from the 4L),
do you have any implementations of the cypress host-code that we can run on the psoc 4 so that we can bootload the 4700S?
Please check this thread - PSOC 4 UART to I2C bridge for bootload host communication
An I2C to UART bridge was developed in this thread to bootload another device. Please let me know if such an application can work at your end. Where the PSoC 4200L device acts as a USB to I2C bridge to bootload the 4700S device.