The performance of the Plaxton plant in Scarborough has been publicly criticised by Cowie, which devoted nearly half a page in its offer document to its grievances.
However, David Bradley, the Transport and General Workers Union's regional official, said yesterday: 'It is not a question of management, but of the market.
'I also deal with the (bus and coach) operators, and they have been hit hard. I want to see a coach building operation in Scarborough.'
Outside consultants have been brought in to tackle Plaxton's financial plight and negotiations have taken place with the unions to amend working practices.
There has been a hiccup, however, with management and unions agreeing that a new bonus system was not working as well as it should be.
'The company has agreed to re- negotiate the terms,' Mr Bradley said. The next meeting with the management is on Thursday.
Meanwhile, the takeover bid looks set to go to the wire when two months of hostilities are concluded on Tuesday.
Gordon Hodgson, chief executive of Cowie, yesterday admitted that the bid would be a 'close shave', even though his company had this week mustered a 28.4 per cent toe-hold in Henlys.
He remained confident, though. 'The pendulum has swung our way,' he said.
Confident noises also emanated from the target's camp. Roger Wood, Henlys' chief executive, said: 'I believe he (chairman Tom Cowie) has fallen far short of what he needs.
'We're very confident of winning. The Cowie bid has not made us rethink or change our strategy.'
Cowie has reinforced its attack this week, by twice stepping into the stock market to buy Henlys shares for 73p cash.
BZW, the company's brokers, managed to elicit the maximum 9.9 per cent allowable under takeover rules, 'and we could have bought a lot more', Mr Hodgson claimed.
Remaining Henlys shareholders are being offered either straight paper terms on the basis of seven-for-ten, or one-for-two plus 40p in cash.
Taking last night's unchanged closing price for Cowie of 121p, the all-paper deal values Henlys shares, up 1p to 67p, at 84.7p.