Hi
If <…> the snake would have bit me.
He should have bit his tongue off! (J)
Bite, bit, bitten/ [size=92]bit[/size]
Have bit – what’s that? 
and when the form is appropriate to be used?
Have bit is the present perfect of ‘bite’. The past participle can be ‘bitten’ or ‘bit’.
Thank you, Conchita.
I understand that. My true question 
was:
are ‘have bit’ and ‘have bitten’ exactly the same? (i.e. whether ‘have bit’ can always (in all contexts) be used instead of ‘have bitten’).
?
Hi Tamara,
To me ‘bit’ is the past form of ‘bite’ and not the past participle. I can only assume that ‘have bit’ has come about by association with verbs like cut, put. let.
Alan
Hi Alan
Thank you. This is what I asked - an attitude.
P.S. Life is life… Even BNC admits ‘have bit’…
It’s not so much attitude as just another of those ‘across the pond’ differences, it seems.
Hi Tamara
Bitten is the standard past participle on the other side of the pond, too. 
If someone said “have/has bit”, then I’d expect the usage to be colloquial. (Or possibly some sort of reference to bits and bytes. :lol:)
Amy