I suspect the big problem is Sissoko is 32 in August, has 2 years left on his contract and is on high wages.
The French league is really skint - huge problems with their TV contract which will give clubs less than last season. So number of French clubs willing to buy a player on high wages is really low.
Sadly we may end up having to retain him (although I hope not) but I hope that Nile John and Alfie Devine get some playing time as both might, just might, be good enough to gain enough experience playing at Spurs to not to need a loan, with a view that the need to play Sissoko reduces.
Winks is more saleable - but not replaceable other than by HG players as we would have too many overseas trained players. So the potential to upgrade isn't there this summer, and most likely scenario is 'one of our own' (or even two or three of our own) showing themselves to be better over the next year or two.