Widening participation is typically 6 years.
Medicine BM6 Widening Participation | BMBS | University of SouthamptonThere is a link to an example of widening participation medicine. You should be able to find it on UCAS, but I'm not 100% sure.
On the Southampton website they state:
In order to be eligible for the programme, applicants must meet three of the following six eligibility criteria.
• First generation applicant to Higher Education (HE) – comes from a family where neither parent or guardian attended university in the UK or abroad and do not have HE qualifications.
• Parents, guardian or self are currently in receipt of a means tested benefit.
• Young person looked after by a Local Authority (for a period of longer than 3 months).
• Current resident in an area with a postcode which falls within the lowest 20% of the IMD (Index of Multiple Deprivation), or a member of a travelling family.
• In receipt of free school meals during GCSE Years 10-11 (for at least one term/2 months) and/or 16-19 Bursary/EMA. (Gap year students may still select this criteria if they are on their first gap year directly after GCE A Levels).*
• A current young carer**, either registered with the local council or with a reference from a teacher/tutor to confirm.
If you fall under three of these then you could do Southampton widening participation because the entry requirements is BBB! You also have a great UCAT score so you should stand a great chance at getting accepted into the widening participation (assuming you fall under 3 out of those 6 categories). If you don't, there are still other universities that could accept you with AAB.
I hope I was helpful, good luck!