Hi. How can I help ?
Hello, my colleague has decided she cannot assist you so I will try and help instead. You may certainly use your British passport to leave Spain and to enter the UK. The fact that you entered Spain in an Australian passport makes no difference. You do not have to use the same passport which you entered a country with to leave it. So if you have a British passport which allows you to leave Spain and enter the UK easier than with an Australian passport, you can use it to do so.
I hope this has answered your query. I would be grateful if you could please take a second to leave a positive rating (3, 4 or 5 stars) as that is an important part of our process and recognises the time I have spent assisting you. If you need me to clarify anything before you go - please get back to me on here and I will assist further as best as I can. Thank you
You are welcome