Reduced rate NI contributions affecting widows

Lilli

My question is:- Who was eligible to pay reduced-rate contributions in 1977 ?
I ask because my husband died in 1973 - I had worked before marriage, but not during. In April 1977 I started working in my late husbands company which was then being run by the Trustees of my late husband estate. The accountant of the company (one of the Trustees) told me I was entitled to pay reduced-rate stamp as I was now a widow. It wasn't until I recently applied for my retirement pension that I learnt this 'small stamp' as it was referred to at the time was, in fact, the Married Womens stamp and, of course, the contributions I paid during the 20 years I worked for the company do not count towards my pension. Nothing was explained to me at the time regarding the consequences of paying this stamp - had it been referred to as a Married Womens stamp I would have queried my eligability to pay it as a widow. I find it completely illogical that a widow could be entitled to pay this contribution as I understand it was introduced for married women relying upon their husbands contributions for their pensions upon retirement. I would add, nobody seems to be able to give me an answer to my question through the various DWP departments.