Phil, as I wrote in TDL very recently, SKY holders should formally accept the Comcast bid because it has become mandatory. So you should have done this by now. If not, do not just leave it, that will only delay payment and could create other problems for you. The process is to complete and return the form you will have received if you held direct. If you held your SKY shares in nominee form, which includes an ISA, then you must inform your nominee to accept the bid on your behalf.
The cash should be paid fairly soon to holders making a formal acceptance, within 14 days according to the document.
On reinvestment, as I said in TDL, after the cash is paid out I will be commenting in TDL on how I allocate this in the various HYPs that held SKY.