As distinct from 'pumps for his feet' presumably? (Ronnie Barker in 'Four Candles' made the same error!)
As to the LAM, I have just perused the website: http://londonalternativemarket.com/general-info/ First Sunday of each month in Leadenhall Street, EC3, which means that free street parking should be reasonably available for anyone wanting to go by car (the City is very quiet at weekends, but keep away from Petticoat Lane area as parking there is still restricted on Sundays). Entry before 2pm is £6, entry after that £7.
Whilst there is a claimed wide range of exhibits, allegedly including footwear, I can see little that is specific. My gut feeling is that most of the emphasis is on activities/interests/lifestyles/products that would be of little or no appeal to me and scarcely justify the trouble and expense of attending. I did once (about 20 years ago) attend what may well have been the same event in London; I found little of interest (and a fair number of rather unpalatable 'exhibits') and left after an hour or so.) However, I am happy to be proved wrong and might be willing to attend, especially if some of us were to meet there socially. Certainly, I agree that the LAM could provide a venue for such a get-together, but would there be any privacy for us - I guess not unless we hired a private room or similar? In which case, why not book such a room elsewhere? All in all, something to think about, as you say.