Tiguan water pump mod

[Fullmel]

I was going to replace the timing belt on my tiguan next weekend but on ordering a new water pump there is a note of Also replace thermostat, IN THE TIMING BELT GUARD ON THE UPPER PART OF THE WATER PUMP HOUSING, SOME VEHICLES MAY REQUIRE A RECESS TO BE MADE BY THE TECHNICIAN
Has anyone carried out this mod and if so could you let me know how involved this is
Sorry about the capital letters as I've just copied and pasted text.
Thanks in advance.