That many will stretch enough for an Upgrade using Avios on a long-haul to the US, but only one way, so you could do a WTP return to USA and upgrade the outbound from Heathrow to US, assuming there is availability.

I'd be tempted to use them for a couple of getaways in Europe using reward flight saver, i.e. avios plus 35 quid for a return hop. With 30k or so that should stretch to enough for 2x return journeys in ET. Or... if you have a partner and want to surprise them, could always book two return tickets to a nice European city and use the Avios to upgrade both to Club (again assuming there is availability). This is only really worth it if you haven't got lounge access through status.

Hope that helps