I don't think a recall petition is allowed unless the Standards Committee of the HofC sanction her, though (or if she is sent to prison or fiddles her expenses...neither of which are relevant here!) Which kind of makes sense, as otherwise constituents unhappy with the way an MP voted or something could start a petition for recall when the MP hadn't done anything wrong.
I agree the division between voting for a "person" and voting for a party is tricky, and I understand the outrage when, for example, MPs defect between parties (as over brexit) as the constituents feel they are being represented by someone who no longer holds the "party values" they voted them in on. But also, I'm not sure withdrawing the whip is as severe a punishment as is being made out. All those Tory rebels who had the whip withdrawn over brexit were readmitted a few weeks later. It's a political decision, and a rap on the knuckles (and a threat that the "party machine" won't support their reelection), but may not affect anything in the long term, especially if the MP continues to vote alongside the party and they haven't parted company ideologically.
In December there was an SNP candidate who was suspended due to alleged antisemitic tweets (Neale Hanvey). So he effectively stood as an Independent candidate. Albeit one with the SNP logo by his name because it was too late to change the ballot paper. He won the seat, suggesting that people were either willing to vote for an independent antisemite (alleged...) or would vote for "anyone with an SNP badge". Interestingly, he was readmitted into the SNP in June.
I do wonder whether MF May be playing a similar game...sitting as an independent, voting alongside the SNP for everything, and then hoping to get the whip reinstated once this has all "blown over". I hope blackford and sturgeon have more integrity than that. Or at least recognise that constituents have long memories.