In the years when I restored a number of Sprint Specials I used to buy aluminium strip from Roy Lambert. He told me that it was used by the National Grid people to wrap around the high voltage cables to stop them chafing where they go over the porcelain insulators on top of the pylons. He also supplied the connectors for the joint at the back of the oval tank. It’s years since I bought any from him, and he has long-since retired from that business, but he MIGHT still have some, or be able to point you in the direction of a supplier. The strip was about 3/8″ wide from memory.