Fixing Punctures / Puncture Repair / Exploding Tubes

Sound like the max clearance you can managed are 25c.
I got some 28c Randonneur lying around to see if it fit your clearance if you want.

28's won't on the front but will on the back, I took them off my brothers to see. Cheers for the offer though, I reckon 25 will be alright.

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Most of my punctures are from valves falling out. Fucking valves.

This happens 1 time out of 9 when I have a puncture, ironically. Minipumps and Prestas don't mix.

You may be able to fit in a 25c Marathon Plus. A good tyre if you really don't want punctures.
I also like Ribmos although not many seem to use them?. They come in 25c too and unlike touring tyres are much lighter (folding version) but still as puncture resistant.

Cheers for the advice!