Yeah... They were crisps. That's a whole lot of carbs, and your blood sugars showed as much. If you had some bifi sausages there wouldn't've been so much as a blip, same with some eggs and bacon. You really want to cut those carbs right back down. Your bloods
could be at 6 after a meal, but you're only just diagnosed, your diet hasn't been tailored to your specific needs yet, and it doesn't happen overnight. I don't know from what numbers you're coming, but for the time being, forget unrealistic goals set by your GP, especially if they're not being very helpful in getting you to those goals. And just so you know... 8,5 after a meal would be alright. You mainly want to avoid double digits, and you want your blood sugars to rise no more than 2.0 mmol/l, 2 hours after a meal. If you can stick to the limited rise, the blood sugars in general'll get lower eventually.
My diet's been like this: Moderately low carb at first, then low carb, progressing to keto, then semi-carnivore, to carnivore. That means I kept cutting my carb intake until there was practically none anymore far as daily intake goes. I didn't
have to go that far for my diabetes, but I had other issues that made going to extremes worthwhile. (It made a difference in migraines and kidney stones, for example). My usual blood sugars hover somewhere between 4,5 and 5,5 now. That includes after meals. I'll still see a 6 after a sleepless night or something, but that's just my idiot liver being a nuisance. I'm five years into my diabetic journey though, and my diet is strict carnivore: meat, fish, poultry, eggs and dairy. Which I can promise you, isn't for everyone and far from easy in social situations. Simply keto or low carb could well be enough for your numbers to come right on down where you want them to be.
I think you've seen this already, but just in case:
https://www.diabetes.co.uk/forum/blog-entry/the-nutritional-thingy.2330/ is basically a low carb / keto starting off point. Learn what contains carbs, start avoiding those things, and start eating the stuff that does agree with you. Your meter'll tell you whether you're on the right track.
You'll be fine, honest. It takes a little while to get the hang of it, and then for your body to get clued in on it all... But you have time.