re = /^.*?(?<digits>\d{2}-\d{2}|\d{2,4}).*?$/m
str = 'ML 12+ (W166) = 12
FREELANDER II 07+ = 07
Kuga 08-12 = 08-12
CRV 2012+ = 2012
RX270/350 10+ = 10
QASHQAI 2+ =
TRIBECA 05 = 05
XC60 ='
subst = '\\1'
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html