Email forwarding

[#1]

I have several domains, and my email client is set up to pick up my email from mail.plus.net and despatch it through relay.plus.net with the "from" field completed according to the appropriate domain.
Each domain is registered through ukreg, where I use their control panel to set the DNS for the domain's host.
I've never been able to decide whether the email forwarding that I set up at ukreg or the one set up at the domain's host is the one that is actually effective.
Could someone advise me which forwarding is the one that actually functions in these circumstances?

[#2]

The emails will be sent to the server specified by the MX records in the DNS for each domain. It wil be this server that hanlde the forwarding. So just do a MX lookup for each domain.

[#3]

Thanks for that. 
The MX records point to secureserver.net, which is Godaddy, but (and I'm sorry if this displays a rather sad ignorance of the way things work) does the mail even get that far? 
Presumably, if an email is addressed to (say) mysite.co.uk, the address of the nameserver will be looked up at ukreg, which is where mysite.co.uk is registered. 
Would any email redirection that was specified  on ukreg's server be bypassed, and instead the mail passed to the host shown in the DNS record (Godaddy), and any redirection be dealt with there?  (The MX record at ukreg is blank, but it is shown as secureserver.net on Godaddy's records.)

[#4]

DNS records are not bypassed.

The first thing is to establish where you DNS records are hosted, To do this you need to do a Whois lookup for the domain. Can use  http://whois.domaintools.com/
For my domain it's

Quote

Name servers:         ns1.livedns.co.uk        213.171.192.250         ns2.livedns.co.uk        213.171.193.250         ns3.livedns.co.uk

Which are actually the new nameservers for ukreg. As you have stated that your MX records point to Godaddy then I will guess that the namesevers willl be from the list below.

Quote

July 27, 2009 — Present ns25.domaincontrol.com ns26.domaincontrol.com March 11, 2008 — July 27, 2009 ns51.domaincontrol.com ns52.domaincontrol.com September 19, 2007 — March 10, 2008 ns43.domaincontrol.com ns44.domaincontrol.com

[#5]

Yes, those are the DNS records - all of the sites are hosted at Godaddy.  So any email "redirection" en route (in this case at ukreg) is ineffective?

[#6]

Correct.ukreg are just your registrar for your domain and Godaddy host your DNS records. Do you remember changing the Nameservers in the ukreg portal? ukreg control the nameservers and can only be changed via their portal.

[#7]

Rereading your posts I'm not sure whether you did MX lookup or just went and look at your records. So just to confirm use http://www.mxtoolbox.com/ to lookup the MX records.

[#8]

Thanks for your interest. 

I think that's conclusive, if I understand correctly.  The MX records points to Godaddy, so any attempt at redirection before that point would fail?