Sorry, but if two qualified and experienced legal professionals (the solicitor and barrister), who're both familiar with all the details of the case, can't agree on what the judge is likely to do then it's extremely unlikely that anyone here can offer a better opinion.
The solicitor might be just 'covering all the bases' by suggesting that the offender should be prepared for the possibility of immediately going to prison, rather than being certain that it will actually happen, but the offender would still be well-advised to heed his advice and pack a bag.