Eddystone P14 - Centenary CMP Competitor?

[M94/14]

Your sight problem itself is an easy to fix. These rifles can use the same front sight inserts as the No.4 enfields. Find the tallest front sight insert you can and install. That should allow your rear sight some room to zero at 100 without hitting the bolt.
BTW, part of the problem, is that there isn't a 100yd setting on that sight, the lowest is 200.