@AlecR When you get it please report what dsl driver version you have on it. The usual version is an 033 one which may or may not support G.INP and does not support vectoring. Also unless it is an unlocked version you may have to get UART and possibly JTAG access to unlock it. On some ISP ones you just need to reflash with the Jazztel firmware via UART access, that firmware has the 033 dsl driver. On others you first have to replace the locked down bootloader via JTAG.
As burakkucat indicates the HG622 is very good on adsl, on FTTC it is almost identical in performance to the HG612 with the old 035 dsl driver that Asbo provided for Hg612's.