If I was supposed to be at Glastonbury by midday tomorrow I'd be travelling now! I was in the area earlier this week and there are LOTS of roadworks and road closures. I've got family who live just outside Glastonbury and it's very busy apparently.
Just had a look, she can do it mostly on public transport with a final taxi journey.
06:36: Thorpe Bay - c2c towards London Fenchurch Street
07:26: get off at West Ham
07:32: tube - on the Jubilee towards Willesden Green
07:56: get off at Baker Street Station
08:00: tube - Bakerloo towards Stonebridge Park
08:05: get off at Paddington Station.
08:13: GWR towards Exeter St David’s.
09:47: get off at Bristol Temple Meads.
From here, on a good day a taxi is a 50 minute drive to Glastonbury. She can’t get the bus because it leaves at 09:48. She ought to book the taxi so it’s there waiting for her. She can do it, if she’s organised and there are no external chaoses on the train or roads.