'the best way to learn is the hard way' couldnt agree more when iut comes to gardening! Just have a go
There is a bit on gardeners world.com called "what to do now" It gives a week by week list of what to sow etc and when to plant out. You can adjust a week either side dpending on whether you are North or South (differing climates) I find garden centres have tender plants far too early. They are OK if you have a heated greenhouse. Otherwise you lose them to the frost and have to buy again (good for the garden centre)
Hi Welshspud! (I'm in Wales too - very soggy at the moment...)
My first year as a gardener was about a dozen years ago now, and I did exactly like you did - sowed everything I possibly could, as early as I possibly could! I sympathise with wanting to get on with it. Don't throw them out - they might be fine - just try to put them in the brightest light possible. I'd even be tempted to put them in your glasshouse during the middle of the day (as soon as you see the first sign of something germinating) and bring them in at night if it is going to be frosty; better chilly than too dark. But then yes, do plan to sow again in march - you'll get better results, and the late sowings will catch up with the earlier ones because they'll be happier. (Seed packets suggest sowing in February because some people have heated glasshouses that they can get up to the right temperature in full light...but really it doesn't matter if you delay sowing til March time.)
Can I just check....when you say you 'covered with clingfilm', have you left enough room for them to grow? I know that's probably a stupid question, but just in case. Ideal thing is to stick some pencils in the pot (say about 6 inches high) and then put a plastic bag over them, so you've created a nice roomy tent for the babies to grow up into....
And I don't think you'll have to water them; more seedlings die from being too soggy than being too dry.
Let us know how you get on! My first year I hardly managed to get anything up from seed (ended up going to the garden centre for young plants) BUT it was fun trying and I learned a lot... and after a few years now I think I'm nearly competent (ha ha)!