On the other hand…I took two and a half hours the other week doing that transfer. Plane arrived on time at T3 from Valencia but then waited 40 mins for a vacant stand. Long queue for the bus transfer from T3 to T5. At T5 connections, boarding pass gate check gates temporarily closed because queue from security scan was back to those gates. Then one hour to get to top of escalators and then another 30 minutes from there to get through to T5. I did think about going landside at T5 but the queue for egates was way back down the corridor. But even my tale of woe would meet your 3 hour 30 mins and hopefully all will be well. But these are strange times.