Hey there. I will be no help at all since I have no experience with turtles. However, there are some folks on the discussions side who can help if you put you question over there. If they are all outside working on their ponds there should be a lot of past posts available if you do a search. Go to the main ponds forum screen and enter turtles.

John, there are patch kits available for all types of pond liners. Since you are located in the U.K. I have posted a link to the Garden Web U.K. Pond forum, where you will probably receive more information on patch kits and where to obtain them. Tally Ho! "Horton" Here is a link that might be useful: U.K. Pond Forum

I've had turtles in my pond for several years. My turtles are Eastern Painted which is very similar to a Red-Eared Slider. I've never had any problems with the liner. The turtles will eat plants like lilies. They never destroyed my lilies, but many of the leaves have bites missing. They will also occasionally eat fish that are less than two inches. I feed my turtles reptile pellets from the pet store and various fruits and vegetables. They love watermelon and cherries. The turtles will leave your pond if they can and it is difficult to keep them in a pond since they are excellent climbers. I have my pond surrounded with plastic fencing supported by rocks. They will need an area to climb out of the water and bask in the sun. I would suggest keeping the turtles in the aquarium during the winter and in the pond during the summer. Wild turtles dig into the mud at the bottom of a lake or pond to survive the winter. Your turtles will not be able to do this and may die if the water temperature gets too cold.

My brother gave me 4 red ear slider turtles with about 5 to 6 inch diameter shells. I've had them in my 55 gallon fish tank for about 7 months. I want to put 2 of them in my pond which is about 16 to 20 foot in length and 8 foot wide at widest. I'm afraid they will rip liner while digging for food and hibernating. Does anybody have experience with turtles in a liner pond? I would like to know other peoples experience in general of having a turtle in pond ie., killing large fish, devasting plants etc. Hopefully I will hear positive experiences from people. I have epdm roof liner.