I've had this problem a number of times with Just You holidays and it's always a talking point / grumble / complaint by everyone on the holiday that it restricts souvenir purchases before the last leg. On a multi-thousand pound holiday I don't think it's too much to ask to include the excess baggage charge to bump up the baggage allowance on all internal flight legs to be the same as the international legs; then the stress goes away.
http://www.vietnamairlines.com/en/before-you-fly/baggage-info/Prepaid-Baggage
Adding £30 to a £3,000+ holiday is not the end of the world for me and I don't think it will push customers over the edge into the arms of your competition with that kind of price uplift. This is the number one change I'd like to see Just You implement - and I say that having done 12 holidays with Just You; or at the very least price it as an option at the point of booking, then if somebody doesn't want it, fair enough - they don't have to buy it.
