The Reeth Three day is a brilliant event. One thing not mentioned about the SSDT for this guy..............the time limits. Plenty of time in the Reeth, very little some days in the SSDT
A Beta Alp is 199cc or 400cc. Based on a Suzuki engine, electric start.
The 199cc is great trail bikes, 400cc a bit top heavy.
This looks to me like a Beta 240 Supertrial with a big seat, never seen an Alp with USD forks, and the LH view show the Beta engine clearly.
But a Beta Alp, it is not.
Spares should be avalable from any Beta dealer.
Use standard 5 1/2" Renthals, I think that is what I used to use, its a long time ago.
What I used to do was cut about 2" of each end, makes the turning circle and control better for the TY 80 rider.