You should be able to replace

Greg K — Sat, 23 Apr 2011 22:25:19 +0000

You should be able to replace the bold portion of the regex you gave with the following:

( ?)

This will have it let the space be optional.

A great tool I use for these is regex buddy. Until I bought (yeah, the B word, but well worth it), I used to have to look up anything but very basic expressions.

That is the part of the regex

pr0gr4mm3r — Sat, 23 Apr 2011 15:02:15 +0000

That is the part of the regex that checks for the space, but I'm pretty sure that if you remove the space, it's more than just taking that out.

I'm not familiar with UK postal codes. Can you describe in words what is being validated?

Also, try playing around with it here: http://regjex.com/ . I have found that tool helpful.