From memory (which is failing a bit!)….assuming there was no associated severe damage to the failed engine and no other failures, it was considered perfectly acceptable by the CAA and Boeing to continue toward destination. The FAA took a different view and I can’t actually remember what happened in the end, but the manuals were certainly not changed as a result.
The tricky bit was in the fuel management. A fair bit of jiggery pokery to get as much fuel out of the tank associated with the failed engine as possible. There would be a few tons of fuel that would be unusable in any case from that tank.