Many thanks for your replies guys. Had to wait till I got the recipe at my fingertips before I could reply.
Am using Neil Willman's (NZer) Express Halloumi recipe and uses 2L pasteurised non-homogenised milk, 14ml of Renco rennet dissolved in water.
Recipe says to bring to 45C (no mention over what duration), which I thought was a bit high before adding the Renco, so waited for 32C before adding/stiring Renco in. No mention of setting time, so waited till at least 30mins before cutting curds. Curds were stirred between 2-5 mins then whey drained removed as much as poss from curds. Recipe calls for stackable containers (no holes), curds put in bottom container, top container was filled with water as weight and left for 5 mins. After which slab was cooked in hot whey until floating before transferring to salt bath.
I am guessing now that the 5 mins pressing time and ~1kg water weight didn't expell all whey from knitted curds, so when I pan fry resulting cheese there is still alot of seepage occuring until they all cook out as the cheese does fry/brown nicely all over. Just that the seepage spits ALOT during the cooking phase until it finally dries out.
Mo