Here's all the other possibilities I had for you...you may want a brew to read them!
Looking at the cake, the middle has dipped/sunk slightly, which can be caused by multiple factors. As an overview, I think there may be a few factors that are causing issues with your sponge.
Baking is a science so if the cake ratios are off, the culprits can be too much fat/liquid or sugar. This can often weaken the structure of the cake allowing it to sink/dip if the proportions aren't correct. The sugar is the cause of the crumbling effect because it sweetens and tenderises the cake as it bakes. However, looking at the depth of your cake and the size tin you mentioned (7 inch) the tin (
depending on the depth size) may be too small for the amount of ingredients/batter you are using which can also cause it to collapse on itself too.
Other factors include overbeating and oven temperature issues. You mentioned that your oven runs hot, so I would suggest getting an oven thermometer for this. (I
always use an oven thermometer to check what my oven says because I once had a Smeg oven that was running 20° degrees hotter than what the temp gauge actually said). That way, you can be sure you are at the right temperature for baking. Another option is to ensure that you never open the oven door during baking, allowing cold air to fluctuate the temperature in the oven, causing a knock-on effect when baking. (That's if you've turned them around while they were baking).
You mentioned that you use loose-bottomed tins for the Victoria Sponge. Personally, I don't. I only ever use them for tarts. I think that a full tin holds the batter better and helps with the structure of my cake because everything is sealed in. (But you do what works for you.)
Ensure when you do bake that all your ingredients are at room temperature and that includes the eggs.
As rule I never ever weigh my eggs (this has caused multiple issues with my other members so I've told them to stop doing it) and when I make a Victoria sponge I use medium eggs not large unless I have to. I always use cake release spray in my tins, too. But I don't use parchment for my sandwich tins, I just use it for my bigger, deeper cake tins on the base.
When the Victoria is baked press your finger very quickly into the top of the sponge. If your fingerprint disappears and springs back the cake is baked, if your fingerprint remains then the cake needs more time in the oven. They should also shrink back from the tin when you place them on a wire rack to cool.
If the dip arises after baking then the cake hasn't fully baked and once the cold hair hits it, it deflates because the centre can be underdone.
I know you mentioned using 160° as your oven runs hot, but I think that may too low for a 7-inch sponge (although, from your picture, it looks much bigger than that). I bake my Victoria Sandwich on 170°/175° Fan Assisted for about 20 minutes. I use 150 grams of marg/granulated sugar/self-flour and 3 medium eggs, but if I have to substitute, I use two large instead of three medium. (My sandwich tin sizes are 8 Inch x 1 Inch deep or to make the Victoria Sponge cake I use a 6 x 3 inch deep tin using the same ingredients but I bake this on the bottom shelf of my oven at 150°C fan assisted for about 50 mins.)
However, because yours looks very deep, you actually need to bake it for longer. If you're happy that the temp works for you, you could place it on a lower shelf in the oven. I have a large capacity oven so sometimes I have to bake cakes on the bottom shelves as per my oven manual. I used to bake everything on the middle shelf, but please check or download your new oven manual and see which shelf it tells you best to bake on. I've had to adapt to different shelves with my new oven because everything doesn't bake perfectly on the middle shelf. If you're doing yours on the middle shelf, it's baking at a hot temp and then deflating as soon as the cold air hits it on the side so it probably needs baking slower for longer.
Check if the recipe you are using is tried and tested, whereby you or other people have had successful outcomes before.
Are you using the creaming method or all-in-one method when you mix your batter? I use the creaming method to introduce as much air into the sugar crystals as I can. (The paler the batter, the better, as there is more air in the batter, helping it rise more.) But I don't sieve the flour in my Victoria Sponge.
I'm not sure if I've now overloaded you with info but I'm just trying to cover all the bases to help you make a cake you're really proud of.
If you need anything else, please let me know.
Best wishes
Angie