My dear MC,
I'm so glad you have a doctor who is finally doing something for you. What a relief! I think I can safely assume that if you do have asthma they have run ABGs (arterial blood gases) and done PFTs (pulmonary function tests). If it turns out to be asthma, being a long-time asthmatic myself, your doctor should explain to you that asthma is also called RAD (reactive airways disease), so you might also be sent to an allergist to see what is causing the reaction. I hope you have better luck than I did. I went for 2 years before it was diagnosed. (Even had a, now thankfully, ex-nurse ask me how I could sit in their lobby and turn blue and scare the other patients!). Two things you will probably inherit if it is asthma. An AeroChamber (for your inhalants-- to get them into your lungs faster) and a peak flow meter (metre, since you are British after all).
The peak flow metre is VERY important. You will find out what your baseline peak flows are and then any time they are below, via the meter, you will need to use your rescue breathers. If they go too far below, you will need to call in. Okay. Now you know why asthma is called the 'pain in the neck' disease. It is, but it is survivable. Good luck.