123-Reg Registrar for my domain - but can PlusNet host email for me?

[#1]

Hi - I moved my domain to 123-Reg a few years ago since they're considerably cheaper for domain-renewals.
I've got a Postfix mailserver configured, but am considering ditching this and configuring mailboxes on my PlusNet DSL account for my domain name.
So my question is this. Can I keep the TAGS at 123-Reg, but move DNS to PlusNet so they can subsequently host email for me?
Sorry if this is a daft question.
Chris

[#2]

Are you seeking both webspace and email to be hosted by Plusnet with just domain administration covered by 123-reg? That can be done, as described in the How to Transfer a Domain help page.
With this set up emails to your domain address would be delivered to the equivalent account mailbox. What sender address goes on outgoing mail would depend on the identity you set up in your email client.