Diva, Google the Family Information Service for your area. It's a council run service that has details of all the childcare providers in your area. There'll also be a support team you can contact for further information. Often I'll get an email from my local support team that's been sent to all providers in the area saying things like "family needs childcare for two children aged xx and xx, picking up from xxxxxx school" and then details of the hours needed. If anyone can fit the bill then they email back and the support team passes their details to the family.
www.childcare.co.uk is another good place to look for providers in your area.
All chilinders set their own fees and to a certain extent their own policies (there are some that you must have by law and the rest are up to yourself) so lots do charge a retainer in the holidays of half fees to hold your place open for you. I don't charge in the holidays, I have young children so holidays off is a bonus to me. I know own I'm not the only childminder who does this so definitely worth checking the above sites, most who do it will have something like "term time contracts available" as part of their listing.
Scottish, it's worth visiting some settings to get a feel for which you like best. Trusting your instinct is important when it comes to choosing childcare. Someone could have an outstanding Ofsted report but if they rub you up the wrong way then you're not going to be happy leaving your child with them and, ultimately, you do need to be happy leaving your child with them. Nurseries and childminders should be able to arrange visits for a look around so once you're further down the line, make a shortlist of a few different providers and see which you like best. You'll know your baby's personality by then too and will know which setting would suit them best.