Most likely reasons for significant fall in such a short period are :
- your deferred pension was cut by a Section 50 order as a means of cutting the deficit; but you should have received a letter from trustees, if this happened.
- more members ahead of you have retired during the year; as retirees they have first claim on the scheme assets on wind up and hence your transfer value is reduced accordingly to reflect what you'd get on wind up.
Impossible to advise you without the full facts. Yes, its possible for your TV to become nil; I have seen that happen.
You'd need to contact trustees and ask for latest actuarial report, and if the scheme is in deficit, what funding proposal did they submit to the Pensions Board by the 30th June 2013 deadline.
Also suggest you contact a former colleague who still works there to get the 'lie of the land' about your former employer's financial circumstances and the state of the pension scheme. People at work tend to hear the bad news long before those who have left service.