Hi OP,
I had this vague memory of Michael Mosley demonstrating the idea of extreme level effort exercising for only 1-2 minutes.
This makes a lot of sense to me as someone who was quite into running. If I were doing a long training run it would be at a steady pace. If you were going to the gym for an hour a lot of that hour would be at a steady pace with bursts of effort. Now if someone told you to exercise for only 1 minute or two minutes your self imposed level of effort is off the scale.
This video suggests 3 bursts of 20 seconds plus gentle warm up.
So can you find 10 minutes once or twice a day to basically do 3 sprints up your road plus a little gentle jog warm up and cool down? How about between when your husband gets in and you start work if you are ready to walk out the door when he gets home? You don't need to worry about work out gear or shower on top of your normal routine as long as you have comfy clothes and good trainers.
I would suggest if possible doing these sprints at least once a day.
Make sure you are eating enough protein for the muscle repair afterwards.
Don't do any training for 3 or 4 days before the test (scary hey but by then it is likely to reduce performance).
Get more sleep in any way possible especially especially nearer the test e.g. you said you would have been on holiday so hopefully you and your partner have annual leave so can get a few proper nights rests.
Eat enough calories each day and plenty of carbs the day before the test. Now is not the time to diet - your performance will be reduced.
Caffeine is known to improve performance so if you tolerate caffeine ok sip a coke or even a caffeine drink shortly before your test.
Good luck. I don't know if you can do it but you can certainly try and see how close you can get.
Good luck!
Edit link: https://m.youtube.com/watch?v=QDFLbEbDUDE