If I was running Lens I'd be holding out for whatever the maximum compensation fee is from Palace, safe(ish) in the knowledge that Sage is clearly our No1 target.
If Parish tries the old 'Here is my lower but final offer, take it or I'll go elsewhere' tactic, I would simply say 'I doubt it mate. Your other options would either cost you much more (Lampard, McKenna) or they are totally free of charge (Dyche, Toppmoller) yet you've chosen not to employ them and to come in for our man instead, which tells me you don't fancy them'.
Besides which, if the guy is under contract then fairs fair. Perhaps he'll throw a strop if he really wants to come to us, perform poorly at work, all that stuff, but that's pretty counter productive for him really. He's not Pep f***ing Guardiola. He's only been a manager for a couple of years, so Lens well be pretty confident that he'll continue to do his best for them if this move doesn't come off.
If it's really £2m or so then I can't imagine it'll be a problem. We've probably lost that much down the back of the sofa over the last few years, such is the wacky world of the premier league.