Garry, could you please explain what the SAR is/involves, and any potential advantages/disadvantages in doing this?
There is an implicit assertion in your original post that you are British. You would then be familiar with the Data Protection Act of 1998 and its various provisions; this is acutely so because you are involved with a foreigner who is vulnerable to immigration controls at ports of entry to the UK.
Your gf now has a pejorative immigration history. My own experience as a practitioner (albeit no longer practicing) informs me that this may result in a premature marriage in order to "set things right". Some premature marriages work, but others result in borken families, domestic violence, women being starved out and resorting to public funds, and the like. So generally I'm against premature marriages.
A more rational approach is to see what the damage is. This means lodging an SAR, Subject Access Request, with UKBA. In the face of an SAR, the only choices UKBA have are to respond or to break the law. They generally opt to respond. Once the SAR has been fulfilled, the extent of your gf's future problems with UKBA can be nailed down. This makes a better informed decision process for both of you. She has to file the SAR, not you. I don't keep the links on hand, perhaps Vinny will be along with some links.
Got your ears on, Vinny?
Other stuff. I'm quite happy to help on the questionable nature of your gf's detention, and the subject is already on ILPA's "to do list". We know about what's going on there, but it's hard getting enough people to step forward for us to get up a head of steam. In addition to what can be done from our end, your gf (or better her parents) needs to lodge a complaint with her congressman. There were enough angry parents stateside in 2007 complaining that they had to react, but it's clear things are sliding back into a state of regression.