GSHP with solar thermal assist

Hi - new to the forum so finding my way.
I have recently moved to a house with a GSHP (Worcester Greenstore - 11kW) heating using UFH (via thermal store) together with Solar PVT (installed some10+ years ago).
I am interested in getting the most out of this and optimising its performance hence my interest in emon.
The Solar thermal feeds a separate coil in the thermal store so on sunny days when the panels are warmer (+5C) than the thermal store (circa 35C) then they contribute to the heating. On colder days they can still be reasonably warm but not of sufficient temperature to feed into the heating.
I understand that it may be beneficial to feed the solar thermal heat into the collector side of the GSHP (when warmer than the ground temperature) thereby “reloading” the ground and using a greater portion of the solar heat and improving the GSHP CoP.
I would be interested to hear views on this or anyone with experience of the set-up to decide if to make the change.