The Kentmere production lines acquired by Harman had to be closed down shortly after the acquisition, due to a host of problems with condition, incredibly outdated materials and machinery, and serious breaches of environmental impact regulations.
Harman moved all production of the lines they continued to market to the same production line as the Ilford branded products.
The "recipes" were modernized in order to work appropriately on the Harman equipment, with materials used by Harman.
The Kentmere films are less expensive for Harman to make - some of the biggest savings come from having less robust anti-halation measures built in.
The Kentmere papers may also be less expensive to make - certainly the line is much more limited.
There was one product that could not be continued, despite the desire to do so - Kentmere's wonderful POP product. It was dependent on equipment and materials that couldn't be modernized.
Basically, Harman got the Kentmere brand, and along with it additional entry into a market - educational users mainly - that benefited them.
It was shut down because Kentmere wanted the space at their factory site for increased packaging (box) production facilities, the company is still trading. Also it was old and added nothing remotely to Ilford's own capacity
No Kentmere emulsion "recipes" were modernised, Ilford/Harman made entirely new emulsions to sell under the Harman brand. They bought the company for its world leading Inkjet products used for Exhibition displays.
The more modern "recipes" (pre about 1987) had been given to them by a Warwick based company when they ceased paper manufacture, they were supposed to pay royalties, but never did. In return the company's sales outlet in Harborne, Birmingham, became the Kentmere professional dealer for the West Midlands.
Around 1987/8 Kentmere advertised for an emulsion chemist, in the then weekly BJP, they almost certainly knew exactly who they wanted from either Ilford or Kodak, and it was specifically to help them manufacture VC papers.
Kentmere was one of many UK companies who only made paper, they never made film.
Ian