Try
www.eurocarparts.comTrack rod ends complete with the steering arm are £26.77 each plus VAT.
They also do track rod ends separately at £11.64 each depending upon exactly what is worn.
Alternatively German, Swedish & French are progressively stocking more parts for the Espace.
www.gsfcarparts.comMy personal preference is EuroCar Parts for two reasons.
Firstly I find it much easier to check parts, availablility and price on their on-line system compared to GSF and secondly they often offer two options.... a cheaper "will fit" replacement part and an alternative higher priced but arguably better quality which is either a manufacturers original part or one made by the original equipment supplier. My recommendation from past experience would be to pay that bit extra and get parts made by Lemfoerder... they are OEM suppliers to the likes of BMW. I had Lemfoerder track rod ends and a new tie rod fitted to my old 5 Series and they were identical to what came off and are still perfect 7 years on.
Of course whatever parts are required you will need to get them fitted and the tracking re-set but your local garage should be able to do that.
Martin