We had changes made to our Standing Orders to enable weighted voting. That means that for each party group, one person is nominated to cast the votes of the entire group on the members' behalf. In the case of the government, it includes the Labour Party and the one independent and one Liberal Democrat member who make up the government. In the case of the four independent members that we have, they cast their votes themselves. Therefore, in their case, if they were not to attend the session, they would not vote, as per a normal physical session.
If there were a technical problem and the individual in question were not there to cast the vote, the Speaker has the option of checking to see if one of the other members of the party concerned wants to cast the vote on behalf of the group, as long as there is an understanding in advance that the members are prepared to do that. However, if there were a problem where the member casting the votes on behalf of the group had dropped out, for example, then we would not proceed with the vote. We would have to have a technical break to bring that person back online, because, as you say, you couldn't proceed if someone were incapable of casting a vote.