Wands and spells

[wapp13]

No: HPFGUIDX 109379

Correct me if I've missed something, but having just read GoF for the 
eighth time I realised that Harry, when he is in the alleyway with 
Dudley, casts a spell without his wand in his hand.  Is this right?  
He says 'lumos' and the wand tip lights up.  I have always assumed 
the wand has to be held my the person casting the spell, otherwise 
why have a wand in the first place?

And a couple of other things struck me while reading this again 
(goodness knows why they haven't occurred to me before now - must 
have been reading with my eyes closed!)  One is that Aunt Petunia 
says the dementors were guarding Azkaban when Lily was hanging around 
with James Potter because she heard them talking about it.  Had 
Voldemort not recruited them on his team at this point?  If not, when 
did they join him?

And another thing - maybe these should have been three posts! - 
Petunia says in PS that Lily was always showing off doing magic 
tricks, turning tea cups into mice during the school holidays.  Was 
magic not banned during holidays as it is in Harry's experience?

Any thoughts anyone?

Mandy Pandy