Where can I go, in the UK, to see clic diesel trains being driven?

The West Somerset Railway from Bishops Lydyard near Taunton to Minehead has some diesel workings mixed with steam. www.west-somerset-railway.co.uk. Chiltern Railways has a single diesel 'bubble car' which they use on many workings on the single track branch from Princes Risborough to Aylesbury. www.chilternrailways.co.uk