Shock Inserts

[Jamie B4]

Wonder if someone could help recently had a look at my shocks and decided that the inserts had been in too long, so wanted to change them. Taken the old ones out ok but when I come to put the new ones in they will not click into place and when I take the tool out, the square part and a red washer are still on the end- Wonder if there is a trick to sorting this out or is it just a case of brute strength?

By inserts I mean 2 x red seals, 2 x small white plastic washers, 1 x big white washer and the square part that seals everything below.