Sales of food saw their steepest drop in three years last month as the summer splurge ended.Read more
Business reporter, BBC News
Along with Mediclinic, the other double-digit faller on the FTSE 250 today is car dealership chain Inchcape.
Shares are down almost 12% to 544p after HSBC cut its target price from 860p to 650p, with a "hold" rating.
Seems a bit harsh, although the stock has had a bit of a rollercoaster year. It started at about 800p before losing ground in March.
It later crept back to about 800p in July - but half-year results that revealed a 15% fall in profits to £161m in July signalled the start of another downward slide.
Inchcape's brands include BMW, Audi, Jaguar, VW, Lexus, Mercedes and Toyota.
Sportswear retailer JD Sports has announced that its chief financial officer, Brian Small, is to retire at the end of this month.
Mr Small, who has been at the company for nearly 15 years, will be replaced by Neil Greenhalgh, who is currently the company's group finance director.
US retail giant Walmart has cut its annual profit forecast following its purchase of a majority stake in Indian online retailer Flipkart.
The company is now expecting earnings per share of between $2.65 and $2.80, down from its previous forecast of between $2.90 and $3.05 per share.
Walmart also forecast that its growth in e-commerce would be about 35% next year, slower than the 40% growth expected this year.
Footasylum has reported a half-year loss following difficult trading in July and August.
The "athleisure" retailer posted an adjusted pre-tax loss of £4m compared with a profit of £2.3m in the same period last year, although total revenues grew to £98.6m from £83.2m.
The results were in line with expectations after the company issued a profit warning last month, which nearly halved the value of its shares.
In its results statement, Barry Bown, Footasylum's executive chairman, admitted it had been "a difficult trading period" as it dealt with "tough conditions" on the High Street.
He said profitability had been affected both by "a lower overall gross margin from higher clearance activity in stores, as well as the extensive investments that are being made to position the company for future growth".
Shares are down 1.8%.