If you are only taking metformin then a low carb approach is a suitable approach and is one many find successful in reducing blood glucose and losing weight if needed. This link is one such approach, there are several meal plans to suit various tastes which may give you some ideas for a way forward.
https://lowcarbfreshwell.com/. It is based an a suggested 130g carbs per day which is what is a good starting point when reducing carbs.
You could of course do your own soups and shakes plan by using products like SlimFast or similar from Tesco though you would not get the support of being on an official program.
Do you know what your HbA1C is so you know what your starting point is for assessing if the changes you make are being effective.
The other thing would be to do some strategic testing of your meals to see if you are eating more carbs than your body can tolerate so getting a home testing blood glucose monitor would help you to do that. Inexpensive ones can be bought on line GlucoNavii, EE2 and Contour Blue are ones with the cheaper test strips. Many find it is a valuable tool in giving them control over managing their condition.
Testing before eating and after 2 hours will guide you, you would aim at an increase of no more than 2-3mmol/l or no more than 8-8.5 mmol/l after 2 hours