insomniac... mate of mine got an assessment second time around but didn't get in - that I know first hand. Have heard of someone who got through second time around but got nothing to back that up - heard it was when economic times were better though. I think your chances of getting through second time round in the current economic climate are slim - they're even turning down decent pilots for first interviews at the moment or making them wait months... maybe when things pick up, second timers may get a look in.
I believe you have to wait a year to reapply or so it was when my mate reapplied.