I think if you buy a S2 or 3, all fab of course, you will pine for a S1 as that is the car you had before.
That is quite possible, Justin.
However, I did have problems with my brand new S1; the seats were not terribly comfortable , the roof leaked and I didn't really like the anaemic sounding engine. It was difficult to hear the stereo (I like music when I drive) as the car was quite noisy. I thought it was in dire need of A/C, not just for hot summer days, but to help demist in the rainy cold winter. Finally, there is the question of age. An S1 is going to be over 20 years old. Even the S3 I linked to is 10 years old. Any S1 is likely to need new bushes and possibly the suspension arms repainted (ha! just like my 47 year old Elan!). Plus the radiator - I have read the originals have plastic ends that crack over time, and need to be replaced.
MMC is important to me as it is one of the special features of the original S1s. Reduces unsprung weight, your wheels don't get covered in brake dust and the disks and pads tend to last forever.
So.. If I found an original, unmolested S1 in yellow or orange with MMC and less than 50k miles for £10-12k I think I'd grab it. There's actually a green one for £9000 listed but it needs a respray. It looks badly neglected, too. https://www.ebay.co.uk/itm/133353317142 Oh, and not MMC (listing says the disks and pads are new).
By the way, if you swapped your Excel for an Esprit, and added an Elan Sprint, I think you'd have my dream garage!