Hi @SJB
Can you share with me your error message too? Or what happens that isn't as expected? Is a value empty? If so which one? Have you watched my video as I believe it achieves what you are looking for.
My first observation is that you have created an unecessary apply to each. The trigger get response is based on a single response. The flow will run each time someone submits that form. The get response details action will therefore only ever return 1 response. It should appear straight under the trigger. This is demonstrated in my video.
Your apply to each 2, which should in fact be the only apply to each (albeit it can be avoided if you are only ever returning 1 result - shown in my video), looks OK. The values array should be the results from the get items and if your filter is working on the get items you should return 1 item (albeit flow will assume it will be more than one and hence puts it into an apply to each).
You need to look at the history of a previous run to ensure get items is in fact returning a match on your filter - expand the output on get items history.
If that is OK, then look at the update item, is it failing? Is the Item ID, the List item ID i.e. 1,2,3,4,5 which is sequentially assigned when an item is created?
Explore the above and let me know what you are actually experiencing or not seeing and I can better advise.
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Cheers,
Damien
P.S. take a look at my new blog here