The origninal capacitors appear to be bi-pole or non-polar, these are the cheapest kind. They do last quite a while, at least a decade, but the value tends to drift, and they are more likely to fail.
However, the values are clearly marked. It appears to be a 25 MicroFarad and a 4.7 MicroFarad.
The capacitors used in the repair are NOT the right type, and they will not work well. At the link I provided, you can get very low priced non-polar Caps -
Europe Audio • Capacitors types • Intertechnik-Bipolar
Janzen, a very reputable company for audio components, has standard Z-CAPS at a still very low price. Maybe £1 each.
Europe Audio • Capacitors types • Jantzen-Std Z cap
If you want to spend more, you should be able to find some for about £5 each, still very reasonably priced -
Europe Audio • Capacitors types • Jantzen-Sup Z cap
Europe Audio • Capacitors types • Jantzen-Silver Z-cap
Unfortunately, 25 MF seems to be a custom size. 22 MF seems to be the standard size. However, if you combine capacitors in parallel, their values will add. For example, if you put a 10MF in parallel with a 15MF, the total will be 25MF. The 4.7MF is a standard value and you should have no trouble finding one of these.
Any of these linked to capacitors will be better than the replacement Caps you have used.
There are places in the UK that have AUDIO Capacitors, it is just a matter of searching them out. Here is a link to Wilmslow Audio in Broughton Astley, Leicester LE9 6RD -
Wilmslow Audio - Audio Grade Capacitors
At Wilmslow, the SuperSound brand capacitors do come in 25MF (£13.19) and the same brand has a 4.7MF (£3.66).
In Electrolytic Capacitors (also bi-polar or non-polar), these are very low cost. 25MF = £1.62. 4.7MF = £1.11.
I personally recommend some type of Film (polypropylene) capacitor like those found in the other links.
Steve/bluewizard