If you’re looking at shared ownership, research staircasing. It has the same costs as buying a house all over again like conveyancing. And if you staircase too much it is hard to sell the property and to find a buyer who earns enough to afford your portion and little enough to pass the shared ownership criteria. They can also increase your rent on the “shared portion” a lot. And again even if don’t staircase, can be hard to sell and find the right buyer that passes the other owner’s affordability criteria. I think shared ownership only makes sense for key workers in areas out of their budget.
Just to add counter balance.
I'm with shared ownership in the SE. Theres a scheme with my HA where I can buy 1% more a year at the original price with no solicitor fees. If I staircase 5% or more at a time there are fees, but my HA usually offers a 50% discount once a year or so. I've gone from 40% to 70% ownership in one transaction.
If I want to sell then I have to go through the HA for three months, then I can sell open market. If someone wants to buy 100%, then I just 'complete and sell' in one transaction (regardless of whether I can actually afford to buy 100%).
The rent portion is fixed at something like 1% increase a year, basically not too much and less than inflation.
Main quirks are I still think selling could take a while, but not too worried as SE is high demand.
Maintenance charges are the thing to watch as these can go up - possibly more of an issue if it's a leasehold block of flats, not sure about shared ownership houses. But on the other hand, I've got no external maintenance jobs to worry about doing, boiler is included in maintenance and heating costs are low.