Arriving LHR (T3) at 12:30 pm, and onward flight at LHR (T5) 10:30pm. Our luggage should be through-checked.

Been to London many times but have never been to Stonehenge. Thinking of visiting Stonehenge on the layover. Tickets are still available for the last arrival time of the day of 4:30pm-5pm, and for all the other arrival times that day. The site closes at 7pm.

What's the best way to get to Stonehenge on public transportation from T3, and back to T5? When would we likely arrive, and what time should we buy the tickets for? We'd rather not hire a private driver (too expensive).

Also, does this make sense, or is it too rushed? Thank you for your advice.