How much time for BA-TK in LHR w/Bags? What should I be aware of?
Would this be on the same ticket or separate tickets? If same ticket then checked through, connect airside via shuttle bus. 2hrs while tight should be fine. If not then as you said you have to collect at T5 after clearing immigration and go to T3 and check them in there - I would leave no less than 4 hours in case something goes wrong.