Abbott are struggling with demand since they were accepted by NICE which is why they have limited distribution to existing customers.
However, many people on this forum have had success getting them from SuperDrug and Asda pharmacies.
Bear in mind, unless the Libre is "pimped" it is NOT a CGM. Whilst it continuously monitors your BG, it only gives you the readings when you "Flash" the sensor. Therefore, standalone, it does not provide alerts in the same way CGMs such as DexCom does.
I encourage you to trial it. Lots of people have found it invaluable. However, there are others who have found they are "incompatible" and get very inaccurate readings from the Libre.
It is also not a complete finger prick replacement - it can be fantastic for providing trends and learning what impact certain foods or activities have on the direction of your BG. But it is not, today, acceptable for a pre-driving reading and the advice I was given was not to use it to calculate insulin dosage.
Finally, when you get one, remember to mention that you have diabetes: you should not have to pay VAT.
