I'm repeating what KARFA posted, you will be escorted landside after offloading yourself and T2 is easily reachable via the tube or heathrow express.

The issue could be the actual escort landside. I don't think after offloading yourself you get escorted landside there and then. I've read on here they happen about once an hour, miss the escort by a few minutes and it could be a long wait for the next. So that's worth taking into consideration when thinking about what time to leave T5.