Great trip! Small group means flexibility, less delay at border crossings and faster loading of vehicle so you can be off. Mostar is stunning yet shelled buildings only 200 metres from historic bridge remind of a terrible European war in modern times. Minibus parks about 10 mins walk from main sights and the 2 hour visit was enough to see main sites and have a meal. Deserted town of Pocitelj is beautiful but sad. Medjugorje seemed artificial commercial to me but will be significant for some. Half hour break here seemed adequate. Short detour to Buna river source was spectacular.
Driver/guide did not speak great English but was helpful and passed around his notes for us to read. Air conditioning essential and very pleasant. Mostar is the hottest place in these parts - temp was 42C on our visit. Just looking at spectacular coastal/mountain scenery almost worth the fare alone!
Overall a great day out with lots of great scenery and interesting sites. Would not recommend trying this trip on your own with public transport due to border crossings.