Both are fantastic models. I'd recommend he drives both to see which he prefers. Personally, we'd take the 'Frogeye' but the Spitfire is marginally easier to work on. Both have pretty good parts availability. As for reliability - by this point in its life, a car is really only as reliable as it's previous owner. If it's been looked after, regularly serviced and looked after, any classic will prove a reliable friend. But please do remember that these are old cars - as such they're not quite designed for the rigours of modern motoring and their parts are getting worn out and will need replacing. It's not that complicated to export a car from the UK to France, but it's always worth doing your research and talking to people who have done it to find out what issues they experienced. As for what impact a 'no deal' Brexit would have on this process, we'll have to wait and see...