In reply to Trinder:
Not been to Crymlyn, but in general on sport routes the loweroff anchors will be on the face of cliff, not on the top, as this stops the rope rubbing over the edge. Therefore they are usually not easily accessible from above. There will often be thick vegetation at the top of the route (as the climbs are not intended to top out), and even if not it will rarely be safe to lean over the edge and clip into the anchor. Your options may be as follows:
a) get a set of quickdraws and just climb the route, sports style.
b) get a clipstick and add least a few krabs/quickdraws and cheat up the route (connecting yourself to bolts, clipping higher bolts, pulling yourself up - always leave quickdraws below you in case the bolt fails).
c) if the anchors are in reach from above, make yourself safe using alternative natural anchors (boulder/tree/trad gear) above the climb and clip them. This requires walking access to the top of the route (not guaranteed) and good natural anchors (not guaranteed). Alternatively, abseil to the anchors. If you abseil off a tree ideally use a sling/short piece of rope around the tree to make an anchor (with carabiner) rather than running your rope directly around the tree, and definitely avoid pulling the rope down if it is running directly around the tree as this will saw into the bark and (slowly) kill the tree.
d) ignore the loweroff anchor and rig a standard top-rope off natural anchors, ensuring that the top rope carabiners hang over the edge, the rope is padded to protect it from sharp edges, and the top is not sufficiently loose that doing so will dislodge stuff onto the climbers as the rope shifts.
What gear do you have, as presumably you have ended up with ropes and rigging gear but no quickdraws or you would just lead the routes?
Post edited at 22:59