When it says ‘patt’ and a number, that means to work that many sts in the stitch pattern. Since there’s 4 sts in the cable pattern when you’re not crossing the sts every 4th row, you would just knit the sts on the RS, purl on WS, and work the dec (p2tog) in the purl sts between them.
Sorry I’m being really thick. I just cannot get my head around the patt4 I can’t work out what stitches I’m going to be doing after the k1,p1 on the ‘next row’
Start over with row 1, except do a p2tog in the p13 section. That means there’s a k4 where the patt 4 is. Just look at the sts - if the next one is a knit, knit it, if it’s a purl, purl it.