Troubleshooting mDNS .local resolving


I am having problems with client devices failing to resolve .local addresses, such as http://hdhomerun.local and http://raspberrypi.local

They either intermittently fail to resolve or fail totally. avahi-resolve -n xxxx.local fails to report them also on my Linux system.

I just wondered whether there is anything specific in my OpenWRT configuration I need to check I have correct?

My local domain is set to .lan which I believe is correct for DHCP resolved hostnames, couldn't really find anything else relevant to check?

option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/'
	option localservice '1'
	option ednspacket_max '1232'
	list rebind_domain ''
	list rebind_domain ''

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'