I’ll second the vote of go to Lockwoods in Leamington Spa, as they know what they are talking about.
They fitted my boots, and when I stand upright in the boots, then the toes do (just) touch the end of the boot, when you “bend the knees” then the toes move back and the boots are fine.
As the guy in Lockwoods told me, If you can wiggle your foot side to side a couple of millimetres in the boot, imagine that amplified down the length of the Ski.
And a good fitting should last at least an hour, so I would’t go at the weekend if possible, and maybe even call ahead.
The other option may be to go to one of the Snowdomes as you can often try boot’s or ski’s there if there is a shop there as well, before buying.