In 2018, I decided to replace the plastic thermostat housing on my 2000 XK8 ( 95,000 miles ). The housing was badly degraded from 20 years of chemical attack, innumerable temperature transients, and erosion from flowing liquid. This year, I wanted to flush the cooling system completely. I removed the hose that comes from the top of the radiator to the water distribution pipe and found the plastic pipe to be on its very last legs probably for the same reasons the T/Stat housing had degraded. It was a loss of coolant event waiting to happen.
The moral of the narrative is, if you are going to replace your T/Stat housing, replace the water distribution pipe at the same time and save yourself some headaches., time, and coolant.