Scots law - can a recommendation by an agent solicitor who has acted in a biased way be appealled?

my sister is having a really rough time. As her ex was messing her around re contact it all ended up in court. her 2 wee boys are in bits every time they have to see dad. The court assigned a non family law solicitor to assess the situation with them both. But he has not seen the boys alone, he has only seen them with their dad, not with my sister (boys adore her). Personally I think there is fault on both sides the way the separation has been handled. But I still think boys best off with mum majority of time. Today my sis got hauled over the coals by this supposedly impartial solicitor and told that he's recommending shared custody which I believe is quite rare. What I want to know is if it is possible for her to make an appeal against this recommendation as the solicitor does appear to have behaved in a biased way?