That's £65.
That sounds very reasonable indeed to me, considering you're paying someone's wages and that it's more durable than a home spray job.
On the other hand, I would consider buying a whole new frame instead, if the frame is basic.
I paid £10 for blasting and £15 powder coat in black.
The same frame I had previously sprayed myself. Stripped with a welding torch then enamel sprayed with an art airbrush. Primer, several coats of enamel and two coats of clear laquer. Looked pretty good when first done, but nowhere near as strong as the powder coat and weeks of faff. As others have said, would never bother again: powder coat for a cheap job or proper professional frame sprayer for quality.