My opinion on this.. having used Newcastle diet method with some success.
If on medication or have any other health conditions seek advice from GP surgery. (It is hardly likely to be a priority issue for them in current circumstances).
Read and make sure you understand info from the Newcastle research team
https://www.ncl.ac.uk/magres/research/diabetes/reversal/
It is 9 years since I first followed Newcastle method. I originally lost 49kg using Lipotrim products, and returned to non-diabetes blood glucose levels within the first 2 weeks, with monitoring from GP and pharmacy, over 12 weeks, break of 6 weeks then another 9 weeks on Lipotrim. Unlikely, but possible pharmacies will be willing to monitor with the current increase in work load.
I regained around 20 kg, over 2 years after loss, due to following NHS dietary guidelines. Discovered LCHF and maintained at that weight most of the time. Have had some success using products from shakethatweight.co.uk sticking to the shakes (which are lower carb than some products).
Over the last few years I have tried LCHF, (maintained weight and good BGlevels) 24 +hour fasts, (lost weight, but had some instability with BG, which kept rising until I ate) . My last HbA1c was back in diabetic range, but I currently am eating very low carb, and have been losing weight. Even with health problems needing steroid meds,.
Confused? Yes, me too.
Bottom line.. If I had known about Low Carb method all those years ago I would have tried that first. Any foods could be difficult to get hold of within coming weeks / months, but meal replacement companies are seemingly keen to sell online. You are unlikely to be able to get close monitoring by GP at moment, and need to consider meds.
If you decide to embark on Newcastle diet, at very least follow guidelines from The Newcastle team.