London are currently eighth in Kingstone Press Championship One with just one win from four games.
Mbu said: “We’ve got a few people to check on, and although it’s nothing major, it’s enough for us to worry about it until later in the week. However, we’re confident we’ll have a competent team to face Oxford.”
He added: “Oxford have started well. They’ve got a few players that have played in this division for a while and, at any level, the more experience you have, the better you tend to go.
“It was a tough game for us last week, and I didn’t expect us to lose by that many points, but there were plenty of positives.
“We weren’t at full strength but we were able to get over the line three times. Now we have to move forward and put that game behind us.”