Any advice would be good thank you
Depends whether that reading of 6 was an hba1c (bottom end of prediabetic) or a random blood sugar reading (not too bad at all). If it's an hba1c then it's an average of the last 3 months, so your levels may have been worse at the beginning of lockdown....
If it's prediabetes then it suggests that your body is incapable of processing too many carbohydrates (everyone's tolerances vary but the massive increase of T2 diabetes in the last 50 years since the "fat is bad sugar is good" mantra came out suggest that society as a whole is eating too much).
Giving up on chocolate, biscuits and cakes is good but you probably need to cut down on your total carbohydrate level - that means reducing bread (including pizza), pasta, rice, potatoes, and be very careful of fruits such as apples which are packed full of fructose. (Most berries are fine).
My suggestion, phone your surgery and ask whether that 6 is an hba1c - if it is then have a read on this forum about T2 diabetes and diet....
And if it is prediabetes consider buying a meter so that you can tell what different foods are doing to your system, some people can cope with more carbs than others and the only way to tell is to test before a meal and two hours after.
Good luck and welcome to the forums.