The raid occurred shortly after an auction earlier this month of the firm’s kit after it fell into administration in June.
The sale was designed to raise funds for creditors after Ilke went under owing £320m.
One buyer said: “We successfully bid for some lots in the auction then were told most things had been stolen when the factory was raided that weekend.
“It seemed pretty well organised with lorry loads of stuff disappearing before it could be forwarded to the successful bidders.
“We’ve now been told that buyers will be refunded their money. Ilke doesn’t seem to have the best of luck.”
Ilke Homes is in the hands of administrators from AlixPartners and the auction was organised by Hilco Valuation Services.
An AlixPartners spokesperson said: “We can confirm that there was a break in and subsequent theft at a property relating to the Ilke Homes administration.
“The administrators are now working with insurers and all related parties to minimise any losses incurred.”