Gomer - as has been pointed out to me - what you can do in a SAR helicopter with a 4 axis FD at lowish levels (my rad alt hold works up to 999' in the hover and quite accurately too) won't cut the mustard in terms of accuracy at 1500 to 2000'.
Having said that, my Bar Alt hold will maintain a pretty good height in the hover at 1500' (we use it for FLIR searches) but it does have accelerometers helping to fine tune the barometric information.
Equally the heading hold is good for +/- 2 degrees in the hover - the only problem would be the ground position - back to lasers I guess (or really good trimming
)