Thank you, Chris. Next time I will try to achieve an even more intense (spice) flavour in the lamb, because once the flavour permeates from the lamb into the rice it becomes significantly less concentrated. As the lamb was so tough after the first session, I added a whole second portion of base and cooked it in the pressure cooker : that had the desired effect of softening the lamb, and by the end the sauce was of perfect consistency, but some of the flavour was lost.
** Phil.