Cut tiles at ridge, how to physically attach?

HI all,

I'm building a 6m x 6m shed (wife thinks its a garage .... ha!), up to the roofing. Using Bristile and Monier terracotta Marseille profile. I've got the roof on up to the last row of tiles before the ridge, of course they aren't a full tile and need to be cut. Upon cutting, the "lugs" that engage the batten to prevent the tile slipping down the roof have been removed as well as the nail hole.

Question is, how do I attach the tiles to prevent them slipping down the roof, roof pitch 26 degrees (damn gravity)? Is the bedding mortar for the ridge and the pointing enough or do I need to mechanically attach them?

I saw somewhere else on the interweb someone had drilled a new nail hole after cutting and nailed them as per rest of the tiles. This is not a big job as only have 50 tiles to cut but want to make sure I'm not creating a problem for me later down the track!!!!

Thanks, WW