New to the game- London store advice needed

I’m new to the game. I’ve made some small FJ and scarf purchases at airport locations but don’t have a store and SA relationship yet. That’s in my plan.

However, I live in the US and am traveling to London for business and want to do some shopping. I know the process for UK stores is different and I don’t expect to walk in and get offered a serious bag.

I would like to get an appointment at for a small leather bag (US nonQB type) if available and additional FJ. Also just shop and look at a selection of products I’ve seen online to think about for next purchases.

Can anyone give me advice on what which store and the approach I should take to get an appointment -are walk in appointments available? Tips for success?