If 40% of the HDR shares convert into Tullow shares, the HDR...

If 40% of the HDR shares convert into Tullow shares, the HDR share price will trade at -

HDR = (6 * 2.02 + 4 * TLW)/10

So if Tullow is trading at $A2.12, the HDR share price should be -
(6 * 2.02 + 4 * 2.12)/10

= $2.06

or 40% of the difference between the Tullow share price (in $A) and the offer price of $2.02

If Tullow strikes oil at Kingfisher and its share price goes up by 10%, we should see a 4% rise in HDR, regardless of whether another bidder arrives.

Interestingly this makes it virtually impossible for Tullow to buy HDR shares on market unless their share price drops below the 0.22289 equivalent value. It also explains why there may be significant trading of HDR even in the absence of another bidder