Device A has a 47µF cap of diameter 22mm. Device B has a 68µF cap of diameter 18mm. Now 47 is more common than 68 and would probably be adequate, but you really want to get the right part where possible. And the obvious retailers appear to be:
Maplin, who have a shop that I can easily cycle to in a lunch time (when it's not tipping with rain). From their extensive range of capacitors they have a total of one high-voltage capacitor, and it is the right value for device A but rather slimmer than either of the two. That's probably OK as you can bend the legs outwards. But the shop only ever seems to have one in stock.
CPC, who have caps of both values but only in the right physical size for device A, and for device B this would probably require an extra hole drilling in the circuit board because the legs are not flexible. They would also charge £5.95 handling fee per order.
RS, who have the right caps for both devices, but the one for device B is sold in packs of five (at £2.85+VAT per piece). And they charge £4.95+VAT for postage.
And Farnell, who have a choice of several components that would fit each device, but they have a minimum order of £20 for personal customers.
Nothing in life is ever simple…