diff --git a/R/00-update_refs.R b/R/00-update_refs.R
index c32bfdf57..5a3fab1f3 100644
--- a/R/00-update_refs.R
+++ b/R/00-update_refs.R
@@ -17,13 +17,15 @@
 #
 ################################################################################
 
+## MANUALLY UPDATE ##-----------------------------------------------------------
+
 #' End date
 #'
 #' @return Get the end date of the latest update period
 #' @export
 #'
 end_date <- function() {
-  ## UPDATE ##
+  ## MANUALLY UPDATE ##
   # Specify update by indicating end of quarter date
   # Q1 June = 30062024
   # Q2 September = 30092024
@@ -70,20 +72,39 @@ check_year_valid <- function(
       "sds",
       "sparra"
     )) {
+  ## MANUALLY UPDATE ##
+  # Check extracts which we do not have data for and ensure this is picked up
+  # by the following code:
+  # DN starts in 2015/16
+  # SPARRA starts in 2015/16
   if (year <= "1415" && type %in% c("dn", "sparra")) {
     return(FALSE)
+    # CMH starts in 2016/17
+    # Homelessness starts in 2016/17
+    # DD starts in 2016/17
   } else if (year <= "1516" && type %in% c("cmh", "homelessness", "dd")) {
     return(FALSE)
+    # Social Care data sets start in 2017/18 Q4
+    # Cost_DNAs start in 2017/18
   } else if (year <= "1617" && type %in% c("ch", "hc", "sds", "at", "client", "cost_dna")) {
     return(FALSE)
+    # HHG starts in 2018/19
   } else if (year <= "1718" && type %in% "hhg") {
     return(FALSE)
+    # CMH stops in 2020/21
+    # DN stops in 2020/21
   } else if (year >= "2122" && type %in% c("cmh", "dn")) {
     return(FALSE)
+    # HHG stops in 2022/23
   } else if (year >= "2324" && type %in% "hhg") {
     return(FALSE)
+    ## CHECK - what is the latest NSU cohort available?
+    # NSU is currently available for 2023/24
+    ## CHECK - What period does SDS data get submitted?
+    # SDS is only available up to March 2024 currently.
   } else if (year >= "2425" && type %in% c("nsu", "sds")) {
     return(FALSE)
+    ## CHECK - what data do we have available for Social Care and SPARRA?
   } else if (year >= "2526" && type %in% c("ch", "hc", "sds", "at", "sparra")) {
     return(FALSE)
   }
@@ -91,6 +112,9 @@ check_year_valid <- function(
   return(TRUE)
 }
 
+#-------------------------------------------------------------------------------
+
+## AUTOMATED REFS - please check to ensure these are used correctly ##
 
 #' Delayed Discharge period
 #'