Those rail replacement arrangements for Avoncliff remind me of St Keyne Wishing Well Halt on the Looe Branch
What the sign does not point out is the rise of over 50 metres from the station to the bus stop.
Quoting myself here ... the other ones where there's a big gap between railway station and rail replacement bus stop that I'm aware of are Cynghordy and Dovey Junction. I have used Dovey Junction to leave the railway network and, sure, it's a noticeable walk - though flat and with no residences anywhere close.
Avoncliff *does* have a noticeable local population though - hundreds of people, big old converted workhouse and an eclectic collection of houses, a pub, a cafe, and lots of walkers including those out for a stroll. As I waited to see the thumper come through, a local train called on the way into Bristol and half a dozen people joined it - and that's just one train in the hourly service there. So close it on a summer weekend and it's not exactly effecting no-one. Bus, I agree, can't get there; taxi and minibus certainly can
Putting Avoncliff in context:

The waterway you see if the Kennet and Avon Canal, crossing the valley on Avoncliff Aqueduct - the railway runs underneath the aqueduct at the end nearest the camera, and it then crosses the River Avon too. To the left if the station car park, from which separate flights of stairs lead down to each of the two platforms. You can see one of the several clusters of houses across the valley and Westwood Village - where the rail replacement bus calls - is atop the hillside in the picture. To get to the bus stop from the station, you walk across the aqueduct, then on the road (yep!) on the far side you loop around under the canal and climb the hill on the road through the trees ... standing to one side to let cars by as they go up and down.