Sonaudax Speaker Refoam

Back in 1979 I built a set of British speakers using an Isophon Tweeter, a Peerless doped midrange, and a 10" Modified Sonaudax woofer. I just now found that the left side woofer foam has cracked open and obviously the speaker is no longer sealed. I have been unable to find specific refoaming kits for Sonaudax but notice there are several generic refoaming kits for example from Simply Speakers and many comments that refoaming is a relatively easy fix. Can anyone tell me how reliable and good the kits are from Simply Speakers or lead me to another source. Thank you.