Is it too late to plant these and would I have difficulty getting them?
Not too late at all and you should not have any problems finding them.
Thanks. Off to search.
I presume you mean 'Japanese Onions' the reason I ask is summer varieties are also on the market at this time of year so be careful what you buy!!
I've never had any luck planting this late. I've always found that they need to be well established before winter, which means planting around October.
I've planted much later than normal and am hoping for the best as I've never had any luck with spring planted sets.