If you have not re-married and not in a relationship just say you are divorced. They will pickup on the fact you where married if they look into your tax affairs, NI contributions, NIS number, did you have kids with your ex? if so you must have paid child support???
The ex is always involved somewhere further down the line. I got divorced in 1977. Married again in 82, thankfully this one is a keeper. I was buying a house in France about 9 years back and had to produce my divorce papers, as I had binned them years ago and could not produce then it held up the purchase by over a month. I had to get new ones , okay did not cost a lot but was a pain in the butt.
When I asked the Notaire what it would have to do with my ex , simple she could under french law been entitled to a share of the value of the property if I had popped my cloggs, same again when buying in Spain. You are just never rid of them.