Grapes against the wall

I have a cunning plan! I will leave it on the trellis till this time next year, then when it starts getting unruly I will say 'why don't we put a clematis on that trellis and take the grapevine down to the allotment?'

Oh I hate to poo-poo such a cunning plan, but I see three shortfallings.

1. The hole you'll have to dig to get the vine out will likely be huge.  Maybe a digger job.

2.  If you leave even the smallest bit of root in the soil, you'll be 'blessed' with new vines cropping up for years.

3. After a year, I reckon the trellis will follow you down to the lotty.