We are planning a train journey on an Arriva train from Conwy to Bath that involves a change from train to bus to train with 5' in between. Does anyone have experience with these changes and the likelihood of making them? And if the connection is missed, what are the consequences?
You don't say which station you are having to change on to a bus. However, 5 minutes connection time is not particularly unusual on these kinds of services since these are designed to connect. If the current closure between Didcot and Oxford is anything to go by there will be hoards of people along the route pointing the way and trying to keep the pace of everyone up rather than allowing dawdling!
If you think you need more time, play around with the journey planner requesting it. This may introduce a much longer time though.
I presume that you are travelling along the line that more or less follows the Wales England border? That being so, you would be changing train at Newport (from Arriva Trains Wales to Great Western Railway) for the journey through the Severn Tunnel to Bath.
This tunnel is a major closure of a very busy route. It is being done so that the line can be electrified. You will often find that changes to train are made with just a few minutes leeway. Do not worry about this. In the event that your train from Conwy is running late and you miss the bus link - presumably at Newport - you can be sure that another bus will leave without an undue delay.
My understanding is that the bus will ‘dump' you on the English side of the Severn estuary at Bristol Parkway where a train will be waiting to take you to Bath. (The train will not necessarily say BATH on the front but some other destination such as Portsmouth or Weymouth). Plenty of staff will be on hand to help you.
PS> It might have been better to post this in the Wales or England forum as many people who might respond do not check the one on Transportation.