MIG wrote:

And weekend trains to Birmingham at Virgin's weekday prices that take
longer than Chiltern.

Not the best time to have posted that, really! The other weekend the
resignalling of the South Midlands and the repositioning of the junctions at
Tyseley (to allow higher speeds for non-stop services) commenced. As a
result, weekend Chiltern services are only running (alternately) to Dorridge
and to Coventry, hourly, on Saturdays and to Dorridge and to Birmingham New
Street (via Coventry) on Sundays until the end of the autumn.