Please confirm Voltage Rating of a Class X Capacitor

[Nick]

I have a number of ex-equipment yellow Class 'X' capacitors marked as follows:-

0.47/10/250, followed by a (Philips?)Part No. 344 41474. The 0.47 is obviously 0.47uf(470nf), but do the following two figures mean (+/-)10% and 250v, the latter presumably being Volts AC. Can anyone confirm this, please?
The capacitors measure about 25mm x 14mm x 6mm.

Yup

470nF, 10%, 250V MKT = Metallised Polyester

If they are the "HQ" ones, they are quite popular with valve audio types. Philips offloaded them to Vishay and finding data sheets for them is not easy - originally they were made by BC who I think merged with EPCOS and RIFA and are now part of TDK !

Such is the convoluted way with components