If you will use the search feature on the forum you will find many post regarding how to change the front coils. Post new questions after you have read some of the post and have a general understanding of what has to be done.
You can get a spring compressor for 30 to 50 dollars. The safe way. I would get the compressor that goes inside the spring, not on the outside. I'm sure others on here that have more experience will be more than happy to help.
I don't know about auto parts chain stores in England, but here, we have "loaner" programs wherein they take your credit card number, charge you, and you have x number of days to return the loaner tool undamaged (and they refund the credit card charge).
I've always used the type that is a long threaded rod that goes inside the coil spring (naturally, shock comes out first) and it has like a curved plate that is inserted from the side between 2 of the coils and you tighten the large nut on top of the threaded rod and it compresses.
But, it did seem to me when I did it on my 67, I could have done just as well with a floorjack under the drum brake assy and being slow and careful once I'd broken the balljoint loose. I just always use a coil spring compressor because I bought one years ago. I guess if you were concerned you couldn't slowly release the pressure on the floor jack and control the coil spring, you could safety wire it or do something.
I will have to say this, I'd taken one out one time and had set the compressed coil (with the compressor tool still tightened down) over on the other side of the garage and it fell over and there is quite a bit of force there, it shot the compressor plate way across the garage and the whole mess clanged pretty loud.
When I removed the coils on my '63, I dropped the lower ball joints, the lower arm will drop very low, and the coil will pop out with very little leverage and very little spring in it. No coil compressor was needed.
I was going to post that procedure as it how the shop manual describes it but was afraid of someone getting hurt. I did mine that way, scared the crap out of me. I had a chain wrapped around it just in case but all went well.