Sleep aggression, what's the best way to handle this & discourage snapping & biting

It seems clear from reading replies to my previous post of 22month old spaniel-lurcher snapping when resting that she has sleep aggression. She is now no longer growling but instantly snapping out to bite whoever is near if she's disturbed. I am trying to clap hands or whistle to awaken her properly before approaching her. She tends to come up on the sofa & "needs" to feel close to people before she relaxes. When it's time for me yo go to bed she growls & snaps when I tell her to go to her bed, then she sneaks onto mine in the middle of the night. She has bitten my friends hand today as he put his hand towards her whilst she was resting. I realise that this is "let sleeping dogs lie" and it could be a protection response, but I would be grateful for any advice please to avoid further injury & upset

I'm no expert but I'd consider withdrawing sofa and human bed privileges. She needs to sleep in her own bed where she can be left alone.

I agree with @Caro Perry Banning her from the bed and sofa isn't about 'punishing' her, or 'making her understand her place', it's simply management. My dog can only go on the sofa when no one else is on it, and can't come on the bed with us - after a few sad eyes, he accepted this remarkably quickly. You probably need to work on making sure she doesn't decide to take a nap right in a doorway, or on the floor right next to the sofa - so teaching things like 'go to your bed' or 'let's go to the kitchen and get you a treat' - if she does settle down somewhere awkward, try calling her from a distance and give her a treat when she moves, or ask her to do something ('Sit! Good girl!') before you move.

A crate is worth considering too.

Try to give her plenty of affection in other contexts to make up for the lack of sofa cuddles. And try to ensure her life in general is low in stress - general anxiety can make us all a bit more twitchy in general.

Try never to correct her for snapping/biting. Once she's done it she's probably feeling confused and wondering what just happened.

Agree with all of the above ...we had to stop one of our jack russells getting on the sofa with us because he too would snap whilst resting or sleeping ...i set up a large crate with a soft bed inside with the door taken off and a blanket over the top and thats where he goes that way everyone is safe ...good news is that sid has grown out of this behaviour (he is now 4 )but i always wake my dogs before touching them ...usually hearing a treat packet wakes them instantly