In 4.10 the spitfires have been reworked, with some new sub variants included, which you will have to create skin folders to use custom skins.
In the left column, is what the skin folder has to be called exactly, the right column the plane is labelled in the QMB.
SpitfireMkVb_________Spitfire F Vb early,1941
SpitfireMkVb12lbs_____Spitfire F Vb, 1941
SpitfireMkVb16lbs_____Spitfire F Vb, 1942
SpitfireMkVbCLP______Spitfire F Vb CW, 1943
SpitfireMkVbLF_______Spitfire LF Vb, 1942
SpitfireMkVbLFCLP____Spitfire LF Vb CW, 1943
SpitfireMkVbM4616lbs_Spitfire F Vb Merlin46,1942
SpitfireMkVc_________Spitfire F Vc(2) trop, early 1942
SpitfireMkVc16lbs_____Spitfire F Vc(2) trop 1942
SpitfireMkVc4xH______Spitfire F Vc(4) trop, early 1942
SpitfireMkVIII________Spitfire LF VIII, 1943
SpitfireMkVIIICLP_____Spitfire LF VIII CW, 1943
SpitfireMkIXcM61_____Spitfire F IXc, 1942
SpitfireMkIXcM63_____Spitfire F IXc, 1943
SpitfireMkIXc________Spitfire LF IXc, 1943
SpitfireMkIXcCLP_____Spitfire LF IXc CW, 1943
SpitfireMkIXcHF______Spitfire HF IXc, 1944
SpitfireMkIX25lbs_____Spitfire LF IXc 25lbs, 1944
SpitfireMkIXe________Spitfire LF IXe, 1944
SpitfireMkIXeCLP_____Spitfire LF IXe CW, 1944
SpitfireMkIXeHF______Spitfire HF IXe, 1944
SpitfireMkIX25lbsCLP__Spitfire LF IXe CW 25lbs, 1944
FB.