Try to find out or work out what each of the protections actuly provide and see if you can understand it, when you do let us know I don't fully understand how I can protect all our holidays yet.
Insurance is generaly very weak when companies/suppliers have issues.
Credit cards are better at protecting monies so if you use a package deal and make one payment that helps.
ATOL only applies if there are flights see if you can work it out here.
http://www.caa.co.uk/default.aspx?catid=27
Abta not sure what/when they apply or what they cover seems to be a TA club and rather than a full bonding protection for consumers here is their leaflet, see the last section.
http://www.abta.com/filegrab/?ref=16&f=heretohelpyou111208.pdf
What am I trying to protect the holiday and the money, primary is the holiday, I can afford the holiday and have the money inconvenient to lose it but not a disaster.
If you use a single supplier then the best way to protect the money seems to be the credit card.
DIY then you have problems, Insurance does not cover you nor does the CC for all the elements.
Flight problems the CC will refund flights but not the cruise if you miss it, so have alternative flight plans(go a day or two early) or cruise ex UK. The CC won't pay for the exctra costs if new flights are more.
Cruise line goes bust you get the cruise money back from the CC but not the flights so have alternative holidays in mind another ship or land.
If you do a TO package through a TA, then you should be covered as long as the TO is ATOL protected.
Needs more investigations when you do make a bookings.
As an a example checkin365 have
ABTA J9642
http://www.abta.com/find-a-holiday/member-search?member=J9642&list=true
and agent for ATOL 2718
http://www.caa.co.uk/application.aspx?catid=490&pagetype=65&appid=2&mode=detailnosummary&atolNbr=2718
The Travel industry is a tangled web of companies.