v8 heater problem.........help needed

hi

been out to a pay/play today but had heater issues from the start

engine up to temp, but heaters only barely warm. pipes in/out not really pressurised and also only warm.

around the course a jubilee clip off one of these pipes failed so i presumed an airlock of somesort, so i replaced the clip, bled the system but still the same

my disco is a 99 3.9 v8 auto
not running a thermostat at the moment

engine only got warm at one point where i discovered the broken clip.

what do you reckon? head gaskets? heater matrix? any ideas welcomed!

Put back the thermostat and then report back.