The rubber tester button on the brake fluid reservoir was very deteriorated – as if it was melting! There seems to be no replacements at the usual parts suppliers but after some Internet research I found a very similar cap for the bmw mini looked the same apart from the colour.
A straight forward swop – at some time I might try dismantling the caps to see if I can swop the button parts into the original cap.
Please see my follow up post at ……. https://mgrv8.info/2025/12/09/mg-rv8-alternative-replacement-brake-fluid-cap-part-2/
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