I'm pretty sure you are covered by your insurance, my car was writen off after being stolen and trashed, I got paid out.
The insurance claims inspector called first asked me for my MOT. I told himit was left in the car, he asked where I last had it certified , I said I travel about so much that I cant remember.
To cut a long story.short he told me he would have to logit in his report 'no MOT'!! There were no computerised MOT's then.
The point is they paid me up.
The no MOT charge, if they charge you will cost around £80, but if you produce a document to prove you have taken it for a test, you are giving the law a chance of also doing you for driving a car with emmision problems after your initial test, yet another fine! And if the court is full of ozone nuts, it doesnt look good.
Wish I could think some thing up for you but thats the best I can do.
I do recall that if you fail the first MOT you are allowed to book it in within two weeks and provided its pretty road worthly you can drive it back to the garage, but double check that, see if you can work it in somehow.
Good luck whatever.
I suggest to ease your mind you give your insurance a ring, you've nothing to lose now, or read through your policy document.