There is a specific rule requirement to disclose any possible disadvantages in the suitability report. The rule (COBS 9.4.7) can be seen here: http://fshandbook.info/FS/html/FCA/COBS/9/4.
Remember that a disadvantage is different to a risk. For example, there is a risk that investments can fall in value, whereas a disadvantage would be that the recommended product has higher charges than the product being replaced.



FCA video guide to pension transfer advice for consumers
Alistair MacDougall Compliance FCA, Pension, Pension Transfer
Although aimed at consumers, firms involved in transfer advice would do well to view the video.