It's a very good point about having a garage I can cycle to, and as a keen cyclist that is viable. However my biggest concern about owning the 3-wheeler is finding enough time to use it. I work full time and cycle to work almost every day, I have a 4 year old son who comes with me most weekend journeys, and my wife has explicitly ruled out him driving on the road in a car with zero crash protection. Other than car events and organised driving days it'll mostly be short journeys in the car, and if I have to add 5 minutes either side to collect and drop off the morgan from a garage I might find myself not bothering. If the car is right outside then I'll be more likely to use it for a 10-minute hop to town.
I'll keep an eye out for a garage. There are some local authority garages 200m from my house, but I understand there is a waiting list. There are also several garages to rent in the area, just nothing close enough at the moment. I'll join the waiting list and monitor the usual listing sites and hope something comes up. Until then I'll see about a sturdy portable garage on the driveway.
Also I would allow 5 mins for removing a cover and putting it somewhere to dry (do folks use alternate covers, 1 drying 1 to use?). Even with a garage I have a 5-10min routine (remove dust sheets, disconnect battery saver, gear up, remove other car car from drive, etc etc...). An M3W is not a convenience journey car IMHO...
Also the M3W does have crash protection and it would be a shame to deny your son rides in such a cool car! Of course drivers around the Reading area can be total idiots, but there are plenty of nice local country rides ...