Thanks for the reply. Yes I have the simplified code. The limit node is set 'Send each topic in turn' queues them up, can take a long time if many topics. 'Send all topics' works better, but it seems to be on a timer, so it may be updated anywhere from 1 second up to the time set. I've learnt a lot about limit anyways!
[{"id":"77dd880e.414488","type":"delay","z":"33871f41.a966a","name":"Limit","pauseType":"queue","timeout":"5","timeoutUnits":"seconds","rate":"1","nbRateUnits":"10","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":true,"x":315,"y":430,"wires":[["237f0796.bc3eb8"]],"icon":"node-red/inject.svg","l":false},{"id":"3de1c9ba.1c1656","type":"inject","z":"33871f41.a966a","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"Bathroom","payload":"2","payloadType":"num","x":170,"y":500,"wires":[["77dd880e.414488"]]},{"id":"bb6859e2.ed1228","type":"debug","z":"33871f41.a966a","name":"Driveway","active":true,"tosidebar":false,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":500,"y":400,"wires":[]},{"id":"501c4dbd.6f7184","type":"inject","z":"33871f41.a966a","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"Bathroom","payload":"1","payloadType":"num","x":170,"y":460,"wires":[["77dd880e.414488"]]},{"id":"a100911f.266cf","type":"inject","z":"33871f41.a966a","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"Driveway","payload":"1","payloadType":"num","x":180,"y":370,"wires":[["77dd880e.414488"]]},{"id":"1bb0165d.5a1a0a","type":"inject","z":"33871f41.a966a","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"Driveway","payload":"2","payloadType":"num","x":180,"y":410,"wires":[["77dd880e.414488"]]},{"id":"237f0796.bc3eb8","type":"switch","z":"33871f41.a966a","name":"","property":"topic","propertyType":"msg","rules":[{"t":"eq","v":"Driveway","vt":"str"},{"t":"eq","v":"Bathroom","vt":"str"}],"checkall":"true","repair":false,"outputs":2,"x":375,"y":430,"wires":[["bb6859e2.ed1228"],["24d18a9a.fb39c6"]],"l":false},{"id":"24d18a9a.fb39c6","type":"debug","z":"33871f41.a966a","name":"Bathroom","active":true,"tosidebar":false,"console":false,"tostatus":true,"complete":"payload","targetType":"msg","statusVal":"payload","statusType":"auto","x":500,"y":460,"wires":[]}]