A right of way is a type of easement. A right to run water (wayleave) is another. There are specific legal requirements for an easement to exist, but I'm not going to bore you with a land law lecture.
An easement for services sounds like it may be intended for water, septic tank, electricity, or something like that. You need specific advice from a competent solicitor on that.
However, it sounds like your concern is that if you grant him a right of way, can he use it to build a small housing estate, with all the houses using this right of way. It's a situation that happens frequently enough, so you're right to be wary.
You can limit the risk by granting a right for the benefit of a single dwelling house only, or only granting it for the benefit of the part of the field he is applying for planning permission on, or alternatively by granting a licence rather than an easement.
It's a technical legal area, but a decent solicitor should be able to advise you, and draft a suitable deed, granting the right, but limiting the risk to you.