diff --git a/frontend/unified/src/App.tsx b/frontend/unified/src/App.tsx
index ad36268..251b74e 100644
--- a/frontend/unified/src/App.tsx
+++ b/frontend/unified/src/App.tsx
@@ -93,9 +93,12 @@ export const App: React.FC = () => {
   if (data === undefined) {
     return <p>Data undefined</p>;
   }
+  if (data.account === null) {
+    return <p>Account null</p>;
+  }
 
   const instrumentSession =
-    data.account?.instrumentSessionRoles.edges[0].node.instrumentSession;
+    data.account.instrumentSessionRoles.edges[0].node.instrumentSession;
 
   const handleChangeTechnique = (
     /**
@@ -200,9 +203,9 @@ export const App: React.FC = () => {
                 // a capitalised "proposal code", whereas the workflows service only accepts
                 // it in lowercase
                 proposalCode:
-                  instrumentSession?.proposal.proposalCategory.toLowerCase(),
-                proposalNumber: instrumentSession?.proposal.proposalNumber,
-                number: instrumentSession?.instrumentSessionNumber,
+                  instrumentSession.proposal.proposalCategory.toLowerCase(),
+                proposalNumber: instrumentSession.proposal.proposalNumber,
+                number: instrumentSession.instrumentSessionNumber,
               }}
             />
           </Stack>
diff --git a/frontend/unified/src/components/SessionSelector.tsx b/frontend/unified/src/components/SessionSelector.tsx
index ca1b689..d3e8be3 100644
--- a/frontend/unified/src/components/SessionSelector.tsx
+++ b/frontend/unified/src/components/SessionSelector.tsx
@@ -14,23 +14,10 @@ enum SessionSelectionMode {
   Custom = "Custom",
 }
 
-type Proposal = {
-  proposalNumber: number;
-  proposalCategory: string;
-};
-
-type Instrument = {
-  name: string;
-};
-
-export type InstrumentSession = {
-  instrumentSessionNumber: number;
-  proposal: Proposal;
-  instrument: Instrument;
-};
+type NonNullAccount = NonNullable<SessionQueryQuery["account"]>;
 
 type SessionSelectorProps = {
-  session: InstrumentSession;
+  session: NonNullAccount["instrumentSessionRoles"]["edges"][0]["node"]["instrumentSession"];
 };
 
 export const SessionSelector: React.FC<SessionSelectorProps> = ({
@@ -42,7 +29,7 @@ export const SessionSelector: React.FC<SessionSelectorProps> = ({
   const [textInputValue, setTextInputValue] = useState<string>("");
 
   const proposal = session?.proposal;
-  const latestSession = `${proposal?.proposalCategory?.toLowerCase()}${proposal?.proposalNumber}-${session?.instrumentSessionNumber}`;
+  const latestSession = `${proposal.proposalCategory?.toLowerCase()}${proposal.proposalNumber}-${session.instrumentSessionNumber}`;
 
   return (
     <Stack direction="row" spacing={2} alignItems={"center"}>