The best way I can suggest is by telling you how I made the move.
In August and September of 2001, I moved to a new home some 40 miles south of my old one. It was in the country and had quite a bit more land, 1 acre compared to 1/5 acre.
As soon as we were settled in, I began the process of moving my 500 roses from my old to my new home.
Because the beds were nowhere close to ready, I potted 30 roses each day (that's how many I could put in my trailer and car and transported them to my new location. The yard was already a mess so I placed them all in a large circle in the front yard and surrounded them with a snow fence. I waited until they went dormant then covered the enclosed roses with a foot or better of oak leaves. (My new home had a number of oak trees.) The fence was placed so I could allow a space between the fence and the potted roses for leaves to protect the sides of the pots.
In spring, I removed all the leaves and pruned the roses in the pots. My plan was to prepare the rose beds and plant the roses over the following few months.
All the roses survived the winter. Unfortunately a major stroke in mid March caused my plans to fall by the wayside. In mid June an army of helpers from the neighborhood, Master Gardener friends, rose society members, and members of my church, came one Saturday and planted my roses. There were no beds. The roses were planted in holes dug in the yard where I planned to put the beds. Over the next two years I managed to salvage most of them and put the beds in good condition.
Most of the roses lived.
I described the above to help you plan your move. With a little advanced planning now, you should be able to salvage your roses and move them. Be prepared to over winter them in a area where they can all be placed together for ease of winter protection. I placed an impulse sprinkler on a tripod in the center of the roses so watering wasn't a big problem. Watering is important as potted bushes will dry out quickly and need to watered frequently. up to the time the soil freezes and the bushes go dormant.
If you have the option of waiting until spring to move your bushes, do so as soon as as you can dig and before they break dormancy.
We saw this home and decided in mid June 2001 to buy it. Closing was on August 4, 2001 so we didn't have much time for advanced planning.
The move was successful and were it not for the stroke, my results would have been much better.
Good luck!

kimric,
If you don't have many roses, (>25), I would suggest just burying them right in their pots, upright, with the bottoms cut out of the pots for drainage. Somewhere in the yard that you will dig up for a bed in the future would be a good spot to start. If you have many, (I've buried many roses in pots so that they would survive winter and never lost one, but in the garage I've lost many. If you need any details just ask.

I was looking at your member page, and noticed your comment about the amount of sunshine in England. I have the same question every time I watch a program from the UK and I tell myself to imagine what a jungle that Island would be if they had a decent amount of sun.:^)

Rob
BC:)