If you can't find an Oly tri that suits, another option might be one or two of the spring duathlons, even the ones before VLM as they're good alternatives to the usual pre-VLM road races IMO. There are a few standard distance (10/40/5) ones around London (Emberton Park, Steyning, Cambridge - although I think that clashes with VLM next year), or for something more hilly the spring ballbuster.