1) No. Just make sure you get the chip first, then do the vaccination. Get your invoice showing when you got the chip inserted. Also for the vaccination certificate, get them to type the chip number on it if possible. If not, have them write it by hand and then have them stamp it and sign it (just for good measure -- i did this with mine as their system wouldn't let them type it in).
2) your vet will almost assuredly not have the form.
3) You can use downloaded copies of the form from the DEFRA website. There are no carbon copy forms.
Here's the pet owners guide on defra:
http://www.defra.gov.uk/animalh/quarantine/pets/procedures/owners.htmOne particular thing of note. You can do the rabies vax and blood test as early as you want. However the certificate, once filled out, is good for 4 months. Wait until about 2 months before moving to fill out the form. In the interim between blood test and filling out form just keep your rabies shots up to date (don't be late by even a day). Many people freak out about waiting too long to do the certificate thinking they'll have to do everything over. That's false. You can have years between blood test and filling the certificate out as long as you have kept the animal current on rabies vax and have all the vax certificates with chip numbers on them dated properly.
Note #2: Make sure you know and control every step of this process, including documentation. Don't rely on your vet to know what to do and have them correct anything they do wrong asap.