The question is not relevant as we do not take DEP commands. When you move from RHS to LHS you move at the the same paypoint. At the moment there are some very junior guys getting commands at LGW, seniority just shy of 3100, I doubt that this trend will continue though and would expect LGW commands to become more senior again in the next training year - I have no inside info on that, it is just my reading of the situation; others will have different opinions.
Command pay gives you no greater amount of allowances etc, just the uplift in basic, so you can work out the amount from that.