Darren, Happy new year,
And well spotted although I need to check that I have not entered it wrong as leeks are NOT good for sowing that early, because of some likelihood of bolting by mid to late summer. So leeks I module sow in late March for planting early May (or outdoor sow mid April).
Beetroot needs to be variety Boltardy and onions can be any variety, salad onions included, all good for sowing in early February. I sow four beet seeds and six to eight onion seeds per module, and have electric heating coils in a bed of damp sand to provide gentle heat from below at 16 to 20C. After 3 to 5 weeks you will see some leaves and trays can be taken off heat then to make way for other veg sown in March such as tomatoes, celeriac, aubergines etc.
