If it is BPt, then they will have to reveal change in SH within...

If it is BPt, then they will have to reveal change in SH within a few days after acquiring another 1% . I bid could come from anywhere, but the most likely candidate is BPT. However always consider the unexpected - like a bid by a smaller player for a bigger one - SxY for DLS , or vice versa , Chinese interest etc etc
It may be easier for stokes to take out DLS now - this would free up some cash for BPT based on % holding and BPT companies could be merged as a later date. There are many possibilities from nothing to various Corp action scenarios