It depends - by the 8th June, you might find, if you don't shear them, they are all dropping their wool and will have bare patches by the time you get to the show. Alot of ours are starting to drop their wool already.
If you do shear them, try to leave some wool on them, but it will still leave lines which will need time to grow out and the sheep will then need to be trimmed. You may be at a disadvantage compared to those that planned to show months ago and so, sheared their sheep in January. Still, a good judge will look though this to the sheep below.
Tough decision for you, but on balance, I think I would shear them AS SOON AS POOSIBLE - like tonight if you can!!
We have two lots of sheep going to the smallholders festival in four weeks time - on lot have to be shown shorn. We sheared around the 7th Feb. The others have to be shown in full fleece, and we will spend the next four weeks tearing our hair out in the hope that their wool won't fall out.