Welcome to the Cake Decorators Q&A

What is best way to apply a seamless tartan around side of a deep cake please

My preferred method of attaching wafer paper sheets is to use a little Trex as the glue, lightly smeared on the cake surface. This helps with sliding the pattern around gently to get a precise match. I’ve tried trex on icing sheets too with relative success but works better with a little piping gel.

There are several YouTube videos which serve as good guides showing alignment on the side and top of the cake.