I saw this add. It's a minimum of 2 years but expected to be perpetual until 777 retirement. Interestingly it's only an extra £1,000 a month for a CN.
Pretty wishy washy wording. Have it written into the contract if that's what's expected.
This looks like an attempt to pinch DHK 777 FOs. Is it worth it for two years, probably not as returning to DHK is not an option once you leave. It would surprise me hugely if this level of pay continued beyond 2 years, once their crewing levels were stable. Don't know what one air management are like, hopefully they surprise me.