2002 KV6 Freelander_ overheats when ACCELerate

Hey little confused here, i have a 2002 landrover freelander that overheats only when i press the accelerator (driving) but soon as i slow down to red light its goes to normal??

no coolant leaking, heat works, and drives normal, carpets dry,no fogged windows,

Recently replaced; thermstat, waterpump, radiator, and flusheed the entire system... bleed it as well.

thanks so much...

By Overheats what do you mean? Does the gauge go up into the red or have you been using the live OBD data?

no the gauge moves up then when i slow down at a red light it drops back to the normal half way

The gauge should never move off the middle. It's calibrated to display this with engine temps between 75°C and 115°C. You would be better using the OBD live data as this will tell you the exact engine temp which would eliminate a faulty gauge.
If the engine is going over 115°C the cooling fan should be running at full speed, this needs checking. The other things to check would be the thermostat and 90° bend top hose are connected the write way round and the water pump is circulating water.