Your calculation is not quite right, because I forgot to mention I took some of the original pension as a lump sum. So there is no way I can see this reaching actually 10% of the original. But I am going to take the lump sum anyway, because I know I won't get any more shocks.
But I also see their insistence that I choose, lump sum or pension, *before* I know how much the pension is, and I cannot see how this can be regarded as honest. If they are just going to purchase a market-rate pension with the lump sum amount, I could get the same pension by purchasing it myself with the lump sum (surely?), so there should be no need for skullduggery. Am I hopelessly naive in imagining they would even want to be seen as honest?