Talk to your midwife about starting at Weston and being transferred if needed.
The problem with Weston is that they aren’t equipped to deal with anything other than a straight forward labour, and therefore send people to St. Michaels.... if you do start at Weston, it may be worth weighing up the transfer time - if something did go horribly wrong, how long would it take to get you there?
I really wouldn’t advise driving as labour is so unpredictable - mine went from 0-100 in minutes, so maybe ask a few friends if they would mind being ‘on-call’ if you do go into labour.
St Michael’s isn’t on a bus route, i think the closest stop is at the bottom of the hill.
It may also be worth baring in mind how bad the parking is around there - if you park in Cabot Circus there is a free shuttle bus to the hospital. There is also one from Temple Meads, so I guess you could even get the train if you were really stuck as they run fairly frequently.
If you labour in the day, the Long Ashton park and ride may be an option?
Or ask to transfer to Southmead as that’s all motorway/A roads from Weston.
I hope you get it sorted! 