At the moment it doesn't look like the TCA is applied at all when calculating the survivor's pension rate. In my case as a voluntary contributor who will make contributions up until my 66th birthday it looks to me like there's no point in deferring. I should just take the reduced pension as soon as I can. My wife would receive a full rate survivor's pension regardless of what my contributory pension is. That's all assuming nothing changes between now and then. I think the whole basis of the survivor's pension is different though, so there's no reason for it to go the TCA route.