Hi all, thanks for the responses.
So I sent a useless letter to them, great!
I have converted the image to PDF so hopefully it has worked. I did not want to ignore their 'letter before claim' because my sister recently did decide to do that when they came after her with the same letter and they did then take her to court and I want to avoid that.
The account went over drawn and was last used 27th jan 2012 and Lowell added the default the 22nd May 2012. - a bit later than I thought so it isn't barred yet then.
Lowell response letter.pdf