Today’s release by the electoral commission of all the parties’ election expenditure allows us to revisit a footnote to the campaign from almost a year ago. The BBC obtained leaked invoices from CCHQ revealing that the Conservative Party was spending around £100,000 a month on Facebook advertising in the autumn of 2014.

Naturally, it was the headline amount that grabbed attention – as it is again today, now that we know that the total Conservative Facebook spend was over £1.2 million.

But then as now, there was a more subtle point. I noted at the time that how the money was allocated was at least as important as the site on which it was spent. Its important to note that large proportions of the advertising spend was on adverts intended to gather email addresses – ie this wasn’t just broadcasting messages, it was data-gathering, spending money to open up what the CCHQ digital team felt was an even more valuable route to communicate with voters.

Judging from today’s data release, that pattern of focusing Facebook spending on email gathering continued right up to the start of the short campaign, a few weeks before the General Election. At that point the invoices switch to listing numbered campaigns rather than specific activities – this may represent a change to focusing on voters in the 40/40 target seats, though that’s yet to be confirmed.

Either way, the new data is a confirmation that not only did the Conservatives spend more on Facebook than Labour (a lot more, in fact), the Party’s digital strategists were focusing that spending, not just splurging it in projecting the brand. Given that those strategists, Craig Elder and Tom Edmonds, are now working for the pro-EU campaign in the referendum, it will be interesting to see if the Leave side match their game.