Hi, welcome to GoY, I would use a john innes number 3 with some added grit for drainage, they like a moist but well drained , fairly fertile soil, if cropping is a bit low, try giving it a feed of sequestrine, as they also like a slightly acidic soil, and you can pollinate them yourself with a small artists brush, Derek.

Yes, mine is in Westland with JI. Its doing really well, in fact its still holding on to quite a few of last years leaves even now! Love it!