Lenstec, an independent laboratory in Wales, has bought Tant Labs, an English lab. The chairman and owner of Tant, Nelson Hawkes, will leave the company, and Lenstec's major shareholder and managing director, Nigel Castle, will become managing director of the two companies together. The managing director of Tant, Gez Donovan, will become the financial director. Hawkes said that Tant would continue to work independently. An expanded sales force will be led by Martin Burroughs, and Joanne Adam of Tant will become marketing manager for the two divisions.