I wouldn't go so far as to say a UK strike threat is "good" for Tata Motors Ltd [TTM], but I believe they'll work things out and Tata won't suffer much in the longer-term.
I would say, the individual who convinced workers to threaten a strike, with the current economy and lack of job availability looming overhead, wasn't very intuitive. Should workers actually walk off their jobs, and be without pay for a week or two, it'll be a long time, if ever, before they make up the difference.
Personally, I've been a union worker in the past (only short-term, summer jobs) and found that they really weren't that helpful to their constituents. I also was in a US Steel area when workers went on strike. The end result was that the union got it's demands, but more than 2,000+ workers lost their jobs completely. And a neighbor said that he and his wife would "never make up" the pay they lost during the actual strike.
If a strike is pending, IMHO, Tata is holding the better hand.... Historically, Tata has been very good to both their employees and their plants' local communities. Currently, too, Tata could probably do worse by building up their inventory. Such threats could cause Tata to consider moving much more production into China. This is not the season for manufacturing-labor to ask for a raise