Hi Les, so you mean add a sub-domain as a new domain, then add * as sub-domain of that? Hmm, I dont think I want to do that. I want to mirror my DNS for domain on Linode with one elsewhere, as a backup service. I can see issues having separate sub-domains as separate zones in Linode, like forgetting to update it maybe. I am trying to configure the remote DNS update for slave zones too, not sure how that will work with separate sub-domains.
Chris, no this is not the same IP as the parent domain. I have sub-domains under my main domain for all my servers, and each server may have various services I access on their own sub-domains, most usually though I add development web sites on sub-domains without having to add a DNS record and wait for it to propagate. I have many multisite managers on a server that creates websites on the fly but needs a domain to work, and I cant wait for DNS. I would need to access the site immediately. So having *.system1.mydomainname.co.uk is a necessity. Dont know why Linode just dont allow it

Thanks