The family of soldiers killed on active service, who had an acting rank, and had held it for less than one year, get the pension of their previous rank. Although the EDM (which you can sign here if you feel so moved) refers to events in 2009, in the last few days exactly the same has happened.

I got this information from a friend currently on duty in Afghanistan. He says:

Please help with this and sign it, it takes just a few
seconds. I have just come from a vigil here in Bastion for an officer and JNCO,
both killed in the last couple of days. One was acting rank - his family will
probably get the pension of the rank below that which he was wearing when he
died!
Seems a bit unfair, as the rule is really to stop people getting an acting rank and then getting that pension if they leave the army within a year while still alive.