I would go for a new steerer or look for a later Raleigh replacement fork, they do show up from time to time on the 'bay. Gran Sport, or Super Course.

The bike was designed for 27" wheels, so decide on that first, checking brake fit if you want 700c. The rear bridge can always be moved, heresy to some, but this frame is on the margins. I do understand though the desire of getting it back running.
Your cheapest route to making it complete as I write will be to buy a donor bike... Even a complete Gran Sport (Gran Sports, Grand Sport) they did change the spelling a bit. Harvesting the fork even...