asterisk users - Dec 2007 - call queuing not detecting caller hang up when call originates from voip provider

Dear all

I've got call queuing working when calls originate from my local site.

After testing I migrated it to calls originating from our voip
provider- it should ring an extension, then queue . All works well
apart from if the caller hangs up when queued: the call hangs around
in the queue as a phantom until one of the extensions answers it and
it is destroyed

Am I doing something wrong? Am using asterisk 1.4.16.2

Relevant part of files:

sip.conf

[voipfone]
type=friend
secret=xxxxxxxx
username=xxxxxx
fromuser=xxxxxx
fromdomain=sip.voipfone.co.uk
host=sip.voipfone.co.uk
insecure=very
dtmfmode=rfc2833
context=fromvoipfone

[s450]
type=friend
context=phones
host=dynamic

[xlite]
type=friend
context=phones
host=dynamic

[consult]
type=friend
context=phones
host=dynamic

extensions.conf

[fromvoipfone]
exten=> 1234,1,Dial(SIP/consult,3)
exten=> 1234,n,Answer
exten=> 1234,n,Ringing
exten=> 1234,n,Wait(2)
exten=> 1234,n,Background(/var/lib/asterisk/sounds/mhqw)
exten=> 1234,n,Queue(myqueue|r)
exten=> 1234,n,Hangup

[phones]
exten=> 1001,1,Dial(SIP/s450)
exten=> 1002,1,Dial(SIP/xlite)
exten=> 1003,1,Dial(SIP/consult)
exten=> _0.,1,Dial(SIP/${EXTEN:0}@voipfone,20,r)
exten=> _ZXXXXX,1,Dial(SIP/01295${EXTEN:0}@voipfone,20,r)
exten=> _ZXXXX,1,Dial(SIP/01295${EXTEN:0}@voipfone,20,r)

queues.conf

[myqueue]
periodic-announce = mhqw
periodic-announce-frequency = 10
music=default
strategy=ringall
timeout=15
retry=5
wrapuptime=0
maxlen=0
announce-frequency=0
announce-holdtime=no
member => SIP/consult,1
context = phones

Any help appreciated!!

John