5d) Knotty problem underlies sportsground's shape (9) R???A???E
14a) Famous English garden ruined within Londonderry's walls (9)
L???N?A??
18d) Room for me and Ed to be rebuilt (7) no letters
19a) Raise bonus at work, investing euros in capital (6,5) ??E??? A???S
23a) Upshot of Open University book about Cuba (7) ??T???E
All help greatly appreciated