Well here's my twopenneth.
I'm due to start in June.
Found out in March.
Haven't had formal offer through.
Haven't had any college info through.
Haven't sorted accomodation out yet due to above.
Get conflicting information each time you chase HR about clearances/references/dates etc.
But I'm pretty sure if you ring them and let them know your plans they can sort something out regarding paperwork and stuff. Only thing I've signed was a provisional offer response and I got that sometime in April or May I think.
Still chuffed though - but it's a bit of a concern I suppose.