Ann: Change in substantial holding, page-10

It only includes any upgrade in current offer. If someone bid higher and Redstone increases to beat then then yes you get the higher bid but only if you accept off market (fill in the form). However if someone bids higher and they don't increase I imagine you miss the new offer as you are tied to Redstone.

If Redstone rebid in a year you miss out. they are locked out of a new bid for a time period after the current offer expires though but I am unsure of details.

That is why, if you are planning to accept (which is a personal choice ) you should hold until near to closing time but make sure you don't arrive late in the post or you miss out. If you don't want to accept do nothing.