If you've not used up your 4 ticket limit, you can buy tickets with another ticket agent. Just make sure you do not excede 4 tickets.
This includes mainland Europe/Ireland as well.
I got told this from ticketmaster on the phone, so have others.
If you ignore this, you WILL lose ALL your orders. If you need more evidence, phone them yourselves.
Thankfully I only bought 1 ticket in the presale.
They sure know how to fuck us about.
EDIT: What a farce. Ticketmaster Manchester are saying presales count, ticketmaster London are saying presales don't count. So basically nobody knows for sure now. So I guess its upto how everybody feels.. is it worth the risk? Unless TM can release a statement... I know for sure I aint buying my 3 other tix with TM!