If you are boycotting Ashley, then you should have been boycotting Debenhams before now, but maybe you weren't aware
He bought 4.6% in January 2014, increased that to 6.6% in April 2014 - https://www.telegraph.co.uk/finance/newsbysector/retailandconsumer/10768782/Debenhams-boss-I-dont-know-why-Mike-Ashley-bought-stake.html
then up to 16.09% in March 2017 - https://www.investegate.co.uk/debenhams-plc--deb-/rns/holding-s--in-company/201703311232391950B/
then 21.2% in October 2017 - http://www.morningstar.co.uk/uk/news/AN_1509374444281274300/update-sports-direct-exercises-further-debenhams-put-option-(alliss).aspx
and in March 2018, it went to 29.7% http://www.thisismoney.co.uk/money/markets/article-5456087/Mike-Ashley-swoops-struggling-Debenhams.html
There was another jump to 23% before that, but I can't find it right now.
His usual method is to take bets that the share price will fall. If the person placing the bet loses, they lose their stake; if they win, they get to sell him Debenhams shares at a price a bit higher than the market value.