Finally, time for the answer. It's flying false colours. Formerly Spanish, it now has a British owner. And the reason I'm finally writing about it again is that I've recently built a model of it:
It's a Hispano Aviacion HA-1112 M1L. True, it was a licence-built copy of a famous German WW2 fighter, but the HA-1112 M1L first flew in 1954, then remained with the Spanish air force until 1967. After that, a lot of them were bought for use in the film "The Battle of Britain", for which they were modified to look more like the aforementioned German plane. But there was no disguising the nose, which was very different from the German plane because the HA-1112 M1L had a British-made Merlin engine, putting the exhausts in the wrong place and also giving it a big radiator under the nose, which I'm guessing is the reason for the Spanish nickname "Buchón" - pouter pigeon.