I usually use the 303 and M3 (done the trip hundreds of times), but the satnav was saying that looked a bit grim so went M5/M4 - Tiverton to Burgess Hill in 3 hours (was 4.5 going the other on Friday on the M3/303)
I drove back from Devon yesterday as well......a constant 16 degrees in the car, and no traffic delays - it was glorious (unlike the trip down on Friday, which was awful)