That was what I thought of with the OP's question. For the RegF Infantry the former SQ (now BMQ-Land) was removed as part of the qualification requirement a few years back when BMQ was lengthened and the DP1 was also expanded to include PO's that were once part of SQ.
The change just recently took place for the PRes Infantry as well where after BMQ Infantry soldiers now no longer do a 4 week SQ followed by a 4 week DP1, but now do an 8 week DP1 split into two 4 week mods.