Have your heathers just flowered. If so take the hedge clippers to them and cut them back to where you can see new green growth. Dig them up with soil clinging to them and plunge them in pots of compost until you are ready to replant. When you are ready to replant, I would take as much soil off as possible and then I would soak the plants in water for two hours, then hose the soil off them to make sure there are no hidden grasses lurking in the roots. When they are all up you will need to make sure you get every last bit of grass as even a tiny bit will quickly invade your heathers again. Dig in some peat if you can get it and then put down the matting. Personally I found matting a nuisance to plant through. I found it easier to replant all my heathers mixing bone meal in the planting soil to give the plants some root food then covered the spaces between with layers of newspaper and I covered those with compost too. Doing it now will give the plants as long as possible to rebuild their strength for next year. Water them in and happy gardening.