Here's the data that the latest scare story in the Telegraph was based on (over a month old report! Slow news day?)
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/641162/Influenza_vaccine_effectiveness_in_primary_care_1617_final.pdf
I would suggest that any effectiveness in oldies is not statistically significant since, apart from care homes where they drop like flies, most oldies are not mixing closely with the general population enough, at school or work etc, to get flu in the first place? Personally I'm waiting for a proper epidemic producing lots more data to see how many of the wrinklies are actually wiped out.
Notwithstanding I'm certainly having mine as it's free and certainly wont make me more likely to catch flu. The only downside is that if i DO catch flu, my carer will tell me it cant be flu 'cos I've had the jab and that it's only a man-cold etc.