If you are looking to get your resin ½ soles fixed, you can expect to pay a repair shop around £20 on average to get it done. However, costs can go upwards of £30 depending on the cobbler.
Resin sole replacement is pretty much the same as leather or rubber sole replacement. The cobbler will start the replacement by removing the old damaged part. Then they will clean the area and do some stitching if necessary before gluing the new part in. They will then trim the excess materials and pin the new part in place. Many repair shops would offer a free polishing if they repaired your shoes.
Don’t know any cobbler? You can do a quick search and find small repair shops in your area. They probably charge less than the big and popular repair companies. Calling each shop to ask for a quote is also a good idea to save you time and energy.