Last year, my hubby made me a light box for my windowsill which worked really well. One side of a cardboard box needs to be cut out, leaving three sides which are then covered with silver foil. The plants are placed in the box, which is then placed on the windowsill and the light reflects onto the silver foil and back at the seedlings. This prevents the seedlings from leaning towards the light, and encourages them to grow straight. It's also a time saver as you don't have to keep turning the plants every day. I shall dig out my light box this weekend in readiness for my seedlings.
It's pouring down again today, so digging the allotment over will have to be put on hold again. This weekend's jobs will consist of sowing more seeds and potting on some of the seeds which have already germinated.