The easiest way would be to set up DHCP on the hAP as you've already done, connect the mAP lite, put all of its ports and Wi-Fi interfaces in a bridge, give the bridge an IP from the hAP subnet and voila

Oh you absolute star! It was that simple! Thank you!

Theatre sound engineer here. I need a simple LAN covering a couple of key areas of a theatre - namely around the mixing desk and in the wings of the theatre. No internet connectivity required. Mainly devices such as ipads, laptops and mixing desks - mostly joining via dhcp with the odd fixed ip for ...