Although even for the longest list of programmes the underlying SQL queries take a small fraction of a second, rendering this and displaying it can take up to 30s. This is because we've used a Web framework to develop Tank Top that makes it easy and quick to develop, but compromises on performance.
In any case I've found some ways to simplify how we render the programme lists, using fewer fancy features from the framework. Things are much faster now. But I'd still like an order of magnitude improvement. I'd like some more headroom so we can add more features to the interface without fear of running out of puff.