thanks for the replies.

i'm not sure whether its the evaporator or the condenser, but its a filter and it lies behind the dash, which apparently has to be removed to get at the filter.

on a d-max its an easily accessible pull out filter, but on some toyotas its located behind the dash.

i will get a couple of quotes for the job and then decide where to take it.

i dont really trust letting a local car air shop remove the dash and then refit it without them missing some screws or connectors and being left with rattles and squeaks, and then having to take it back and argue with some dimwit teenage greasemonkey, at least with toyota it should get done properly even if they need to do it twice.