Stuart, it is really too late tyo plant them, but plant them anyway when you can. They will probably not do very well this year but might be better next. You can always buy some more later this coming summer.
I am assuming that the bulbs are not dry and crinkly or full of blue mould, in which case just put them in the rubbish bin.

If the bulbs still look fine, why not plant them in a tub or container in compost and place outside? At least they'll be planted and you can transfer them to the garden proper after they've flowered (if they do, as its really a bit late)

I've been caught out these past few months and have just planted a load in a couple of tubs too! As long as the bulbs look OK and are firm.....they will flower.
This happened last year with a bag of "freebies" I got from a local garden centre and they gave me a wonderful show - albeit a wee bit later - which was all to the good - it spread the season!!

Thanks for the help. I will indeed plant them in a tub and see what happens.