Hi Jourdain,
That happened to me in January. I brought a jacket from Matalan to wear at my niece's graduation in Hull (I live on The Wirral). On the morning of her graduation I put the jacket on and wondered why it wasn't sitting right, then saw the security tag. I was sharing a room with my sister so she suggested a strong magnet might work. We went down to breakfast (had to be at Guild Hall for 09.30) and asked if the Travel Lodge had a magnet, which they did (needless to say it didn't work). I decided that since the tag was close to the side seam if I kept my arms down by my sides you wouldn't be able to see it.
We had to park in a car park attached to the shopping centre in Hull and as we were walking through the shopping centre I had a brainwave. My sister, niece and her boyfriend went ahead for the graduation and I made a detour into Dorethy Perkins. I explained what had happened (my accent probably told them I wasn't local), and they very kindly removed the tag for me.
I made it in time to see my niece graduate, and was able to applaud her and all the other graduees (if that's a proper word) without embarrassing the whole family.
You have nothing to lose by going into a shop nearer to home, explaining what happened and asking if they could help. That is of course if your OH hasn't managed to remove the tag.
Good Luck.