I hear your frustration! We have been put on hold so many times due to my medical conditions, so even when we thought it was our time, we were faced with another delay. Please don't consider your holiday as wasted money, enjoy your holiday, my husband and I always came back from holiday with higher hopes and happy dreams! Your holiday is a great time to reconnect and I found helps to put everything in perspective.
I've not found any UK insurance that would cover IVF but BUPA do cover some investigations ( I had a scan, laproscopy and HSG scan ) all covered but only if they are investigating...ie suspect cysts.
I hate the cliche but time does go by quickly, (although Mondays seem to last forever, don't they

) wishing you lots of luck in your journey!