what do you do on boxing day?

I read somewhere that boxing day is when you should plant onion and leek seeds, only I haven't purchase the leek seeds yet. I did onion seeds on boxing day last year and they were sucessful, transplanted out into the garden. This year I am trying red onions. This is the greenhouse in late May -2005, it arrived late October-2004, gifted from somebody no longer wanting it. I ts 6ft x 7ft which seems an odd size, but its over 30 years old so there may not have been standard sizes at that time. These two benches are from B&Q, last years Christmas present. I have another potting bench which was handmade by a local joiner, its at a better working height, and two shelving units of the "outside greenhouse" plastic covered shelving. You can never have enough shelving it seems, also the green house will never be big enough, even if its twice the size! As you can see through the glass its right on the road side but hasn't suffered too much from vandalism, four windows broken in the first four weeks, then they must have got bored and there's been nothing since.