I have looked through my Westwood brochures, and two pages detail the Lawngroomer which may be of help. Attached as a PDF.

Westwood used to have instructions on their website for the range of tractors but not implements. Anyway, the company is now defunct, and the website is no longer available.

The Lawngroomer is early 1980s. In the mid-1980s it was given away as a free accessory when a new Westwood tractor was bought.

Up until early 1986, it was listed (Mark 1) with the sprayer, rake, brush and spiker at £175, with the lance, slitter and roller (each £29.50) listed as additional items.

Ransomes bought Westwood in 1986, and later that same year the *NEW* Mark 2 takes over and is listed at £175 including the sprayer, rake, spiker, slitter, and a free hand-held spray lance. I assume the Mark 2 is the model with the integrated tanks – it appears in Westwood/Ransomes adverts before being deleted from price lists in 1992. Subsequent Westwood brochures show a separate wheeled aerator and a dethatcher instead of the Lawngroomer – presumably these two were bought-in items.

It does look like the slitter and others were fitted on the back in place of the rake bit. I’ve found a photo in the 1985 brochure with the slitter attached.

Until I looked, I hadn’t realised that the Lawngroomer Mark1 was such a short-lived attachment – just 1983 to 1986.