Broadfieldz was about an hour away from extreme, but they arent trading any more.
The seats have all the covering stripped off them, then new metal frames for the headrests welded on & new padding for the top area. Whilst the covers are off, you can replace any damaged springs or compressed padding so when recovered they should be as good as new. I found the MR2 standard seats in my 96 very comfy & that has done 100k miles, 50k of those with my fat ar5e on it!!!!
Once modded, any car trimmer/upholstery place should be able to do them to your exact requirements. Custom car interior and trimming isnt cheap though, it may be more cost effective to buy aftermarket ones.