Hello, I hope the following assists you.
To access the retractor mechanism means removing the inner "B" pillar trim and inner sill trims. Don't worry about the airbag symbol this refers to the curtain air bag that you won't be anywhere near. The air bag system is connected to the seat belt on the buckle in the form of a pretensioner and you won't be touching this.
Remove both door aperture seals from the "B" pillar area, move the seat belt height adjuster to it's lowest position. Remove the screw cover that has the air bag symbol on it and remove the screw from behind, move the top part of the trim (it unclips) and then undo the two screws at the top of the lower trim. You can then remove the inner sill trim by unclipping it, this reveals the seat belt retractor mechanism.
If you need to unbolt this from the body but to pull the belt out the retractor must be in a level position otherwise it will lock.
Below are some diagrams to assist you.
Let me know if you have more questions regarding this and I'll reply as soon as I'm able to.
Your help was good and got the belt mechs out for me ,tho not the problem .Which I found was threads from the belt had tangled around the belt spool,.After some fiddling with stiff wire and a trim with scissors.I managed to sort the problem.
Thankyou for you help ,I would not have tried it without your info.