In reply to Alexander_Metcalfe:
The requirement is 16 hours (2 days) and contain an element of assessment. It is recommended that it contains some "outdoors" but that is not an actual requirement (though bloody boring if stuck inside for 2 days)
I would hesitate to listen to recommendations of any one organisation as in the end it all comes down to the ability and experience of the trainer. I would suggest you should be more interested in recommendations of individuals trainers.