Presumably trains are held outside while waiting for a platform, so by definition something will have to leave before they can be platformed(eugh!). Not an easy one to solve (see this thread for further examples
https://www.railforums.co.uk/thread...-of-on-gtr-great-northern.283224/post-7290425). But some decisions seem totally inexplicable.
Actually, in all cases its happened there has been nothing on or recently through the booked platform 3 at Basingstoke, just red signals for no reason on approach.
At Exeter St David's, it's usually the crossing not being activated in time meaning slow to a stop, then immediate start which, with the almost normal late running, means missing connections (except Barnstaple that they usually hold). Unless the preceding train from London is late, there is usually nothing in front of the London train at Exeter on Platform 4 (or indeed the whole way from Castle Cary) and the Barnstaple train, that would cross the track in front of the London train if it left on time, is usually held for connections.
I've lost count of the number of times my late running London train has been held outside, so it arrives into Exeter at 23.5 past and then they let the 25 past Waterloo train go 40 seconds early (as is allowed) and so you miss it. The Waterloo train then sits in Exeter Central for 3+ minutes so there is no issue with holding it for 2 minutes. Instead, you miss the connection meaning a one or two hour wait depending which station you are going to.