BYE Chart, page-86

What multiple is appropriate?
As per the May 2020 presentation, Certified 2P (Proven and Probable) Reserves = 17.4mbbl (as at June 30 2019)
Prospective Reserves = 42.3mbbl

https://hotcopper.com.au/threads/ann-investor-presentation-may-2020.5403142/

I understand that the targeted production rate is 10,000 barrels per day (much higher than Badger's table projection at around 4,000). That production level may be a bit delayed, but that still is the target I think.

10,000 barrels per day = ~3.5mbbl per year.
3.5mbbl x 5 = 17.5mbbl in total which is the current certified 2P reserves as of June 30 last year (prior to the drilling at SM58)

Obviously this doesn't take account of any PV discount rate but 10,000 barrels is 2.5 times Badger's targeted production rate so I think we can fairly accept that 5x is a very low multiple based on existing certified reserves which do not take account of SM58 at all.
This does not take any account of the declared Prospective Reserves of 42.3mbbl either.
3.5mbbl x 10 = 35mbbl, so a 10x multiple may be a more appropriate number but still very, very conservative if you are assuming a production level at only 4,000bpd as per Badger's table.

The technology Byron has been using to identify its drilling targets has improved its success rate on exploration drilling to above 70% and there are 25 identified targets ready and waiting to go with SM69 being next cab off the rank.
Byron's costs per bbl are in the lowest decile at ~US$10.
Based upon this assessment I think it is safe to say that BYE is extremely cheap at current levels. Using a 5x multiple to value the company would be way too low IMO.