If she only returned to this country at the end of 2008, and this is presumably the first time she has obtained rented accommodation here, then I would have thought it was only her actions from that date that were relevant.
She may have had her Spanish property up for sale previously when, I assume, she was still living in it. She then took the property off the market.
If the property went back on the market when she returned to the UK I would say that this is the date from which her 26 weeks (or longer if reasonable) would commence.
