I do know a lot of clinical psychologist working in forensic settings and there jobs overlap but are slightly different to their pure forensic peers. May be biased but I think the clinicals have a lot more flexibility and their route is more straightforward, whereas getting Stage 2 for the forensics is a considerable challenge.
Sinnie is spot on, but I would say the Stage 2 for the forensic psychologists I know has taken 4-5 years because of having to fulfil the HCPC requirements, and having to do this on top of a regular job. I think the DForenPsy courses that are springing up make things more structured, so those are worth looking into.