Hello Rhys, I would wait. Your 8-8C is a snapshot of current conditions only.
If you try, you may succeed, it’s just risky as March can bring cold weather… and even with fleece over, the sun is less strong now, for helping germination, than in say three weeks time.
Early sowings carry an element of gambling. I have tried so many times that I now prefer to wait until the odds increase in my favour, usually starting in mid March outside.
