You won't have unless you're actively involved politically in some way outside of just voting once every 5 years. It's one of Corbyn's organising projects: https://thecorbynproject.com/

There have been longstanding rumours about backroom talks with union leaders about spinning out a new party and taking the unions(and their memberships) to it. But this partially hinges on having leftist leadership in all of the major ones which isn't the case at the current moment in time. There are 2 union leadership elections between now and the next election that will be fairly major in determining whether this strategy can work down the line.

PR is never going to happen without mass unrest there is literally no incentive for either party to support it without a political collapse occurring where it is used as a concession to prevent further unrest. Both parties benefit from FPTP and literally every leftist would immediately leave the labour party for proper democratic socialist and communist parties that would very suddenly gain massive amounts of power because more than a third of the country would vote for them if not for FPTP. It's just unrealistic to even discuss it because it's not happening, the libdems sank that ship, you can thank Nick Clegg for that, President of Global Affairs at Meta, best bud of Zuckerberg with the same powers as him at the company.