Hateful things!
If you want to saw dados like this, at least use an American style dado set - a couple of sawblades at the sides, spacer washers between and a couple of chipper blades as needed.
You can buy US dado sets easily in the UK. It's a bit harder to find a saw that can use them. You need an insert made up for each width, you need a decent length of arbor on the saw, and if you're industrial(ish) you have to worry about PUWER 98 and the spin down time limits, which are quite hard to achieve (heavy DC injection braking will unscrew a basic locknut).
Wobble saws are a pain to set up for accurate width and absolutely fecking lethal for kickback.