These mortgages aren’t available from any lender, and they’re only niche products offered by only a handful. You can look for these joint ownership mortgages in a high street bank branch, in mortgage magazines and journals, or by speaking with an independent mortgage broker, which we suggest.
If you walk into a bank, they will only be able to sell you their own joint ownership mortgages, which might not be the best option for you. If you talk with an independent mortgage broker, they will work with you and will be able to explore the “whole market” for the best joint ownership mortgages. Try this Metropolitan Mortgage Corporation

First-time buyers will find it difficult to get their foot on the property ladder and purchase their first home. There are, however, a variety of choices open to you if you find yourself in this situation. Shared ownership mortgages are one option that may be ideal for resolving the issue.
Shared ownership mortgages were created to assist you in obtaining your first home. They are basically part-rent, part-buy schemes that are extremely common among first-time buyers.
After the 2008 credit crisis, the supply of joint ownership mortgages has decreased, and obtaining what is essentially a 100 percent mortgage has become extremely difficult.
When you purchase a share of a property in joint ownership, you are purchasing a portion of the property. This can range from 25% to 50% of the total value of the land. The benefit of this arrangement is that it allows you to purchase a property that you would not otherwise be able to afford, as well as allowing you to raise your share of the property at a later date if you so choose.
On the negative side, this means that if the property’s value rises, you’ll only get a portion of the increase.