You must declare it - chances are they will know anyway - to any lender you try to remortgage with.(posted 8304 days ago)Chances are normal lenders will turn you down - some without even considering you further. Others may consider how long ago it was, and allow you to comment on the circumstances. If you do manage to remortgage it will probably be at a premium because you'll be seen as a higher risk.
If your bad times are now behind you, best thing to do would be to get the SPO removed or not put on in the first place. In fact, if you can avoid it at all, do so. Otherwise, accept you're stuck for a while and make the best of it.