I think, some airlines for the sake of medical equipment will allow two bags, one for medical supplies,
QUOTE]
I never even thought of enquiring about this
- what a good idea,
thanks.
It's always worth a call to the airline, or even better to security at the airport you're flying from. The one bag per passenger is generally a country by country enforcement, and the UK is still strict in general on this. As such the return flight is unlikely to cause you an issue.
It is also critical to have a general letter (e.g. not with specific dates) from your GP stating you need to travel with insulin, pens, needles, lancets etc. If you have any controlled drugs on prescription these under Home Office regulations have to be documented specifically with quantity, dates of travel, airports and flight numbers and times. DO NOT get this added to your generic diabetes letter.
Your GP may charge you for one or both of these letters, best if you need both to get the generic one done first and then the controlled substance one done later. They might not charge you for either.
The controlled drug one technically is required even if you aren't carrying the drugs with you, but if you've taken them recently or are wearing a patch of the drug you will have traces of it on you still.
When you consider how much duty free gets put in the cabin on each leg of the journey, one bag of medical supplies is unlikely to be an issue.
If they want to take the bag from you for 'storage in flight' make sure it it NOT going anywhere near the hold and will be in the cabin space - you will need it during the flight to inject, but insulin is 'killed' at very low and high temperatures.