I have a 2 ltre Zetec in My '61 DHC along with a T9 transmission. The Moss box is not exactly light. This DHC had a Fiat Twin Cam and a 3spd automatic when I bought it. My Daughters loved it, but I needed more power. As it turned out this was an inexpensive conversion for Me, as a Northern Californian knew of all the parts I would need and also had a friend that had them. Incl. a Burton Sump and other items I would need. If I lived in the UK I would source a 4 Seater with a Ford CVH engine. Toss the CVH into the trash barrel and source a more modern Zetec or Duratec engine. Keep or get a 4.1 rear axle and have some fun for, hopefully, a sum that will not break Your budget. I love these engines, they like high RPM's but do have some grunt. Just do not bolt ever do dad You can find and increase the weight. The trade off for Torque/Horsepower is Low Weight and a smooth driving style. I did not originate that last statement it is well known amongst the Racers.
I bought Colin Musgrove's book Years ago, My first book 1982 I think.