The tomato seed I sowed on 31 March failed to germinate. On 18 April I uncovered the containers and found the compost was dry. I had assumed that, because there were drips of condenastion on the inside surface of the clingfilm, the compost was moist. I added more water, and eventually most of the seed, including the coleus, has germinated. However, there is only one healthy-looking Ailsa Craig seedling (this may well have something to do with the small 3 caterpillars I've found in the compost), so today I sowed a few more.
The courgettes have germinated - I've put the bigger one outside in a crate.