I live near Dorking, Surrey. This weekend there are no trains on the radial Epsom to Dorking route and the replacement buses are needlessly complicated, apparently because two TOCs share the route. It set me wondering where there are other routes that are more or less equally shared by different TOCs with very similar service patterns and provision. In the Dorking case SWR and Southern operate what are essentially similar suburban services along the corridor, so neither offers a fast vs. slow service, etc. I can't think of anywhere else in the UK where this situation exists, but I'd be surprised if I've not missed examples.