Nicky
I get bunions from shoes and boots which are too narrow, and from nothing else. Once I switch to a wider fit, they die away. Temporary solutions are felt (best) or foam (adequate for a while) rings, centred on the bunion. I hold them in place with a strip of zinc oxide tape.
If your feet are too numb to feel (and anyway problems like bunion pain sometimes come only after 20 miles or so, or, once bunions are present, are tender and painful at the slightest touch), try the theoretical route.
Measure your foot width by tracing the outline on a sheet of A4 paper, or rather get someone to do it for you as your foot needs to be loaded with your body weight to give the ‘in use’ width. Then check your width and length against what is shown on manufacturers’ websites. You may have to search around to find this info.
I use New Balance 2E width, and find them fine, but NB are moving out of the walking: trail field and concentrating on running: road, field and track. Other manufacturers do offer wider fit shoes, but, confusingly, not using a standard width designation. Some use 2E, some W, others just say ‘Wide fit,’ yet others something else.
In my experience, you need to go for a shoe/boot that is specified as wide, and not rely on someone saying that a particular company’s ‘standard width boots are wider than normal.’ Also getting a shoe fitter to steam or otherwise manipulate the leather on a standard width shoe/boot to widen it is not a long term solution. The leather shrinks back eventually. Remember that the distances we walk are three or four times what the normal (in both senses) mountain shop customer walks. What might be all right for 10 -15 miles may not be all right for 30 - 45 miles, let alone the Hundred.
No experience with Whalleys, sorry.
Good luck
Elton