‘Dado Grooving‘ or otherwise called ‘Trenching’ Planes are first noted in the 1897 MARPLES catalogue where they are listed under ‘Trenching Planes’.
They were always only made up to 1 inch in cutter width with an accompanying double slitter blade to score the edges for easier cross grain work. The main blade was skewed. The lesser quality of the two sorts of plane had only a wooden depth stop whereas the ‘expensive’ model had a brass screw stop.
In 1909 there was an Item number change, and the planes retained these numbers and with the same image until no longer manufactured:
The 1921 catalogue entry shows the same:
1928 [immediate below] and 1938 [ below] catalogue entries were identical, except for prices. You will note that they are now listed under ‘Dado Grooving Planes‘.
The 1959 listing is here:
The last listing that I can find is in November 1963, but by March 1964 they no longer appear to be offered for sale.
The photos below are of a 7/8″ Trenching plane #2941 with brass scew stop.