Assuming that you didn't reoccupy the property on your return to the UK before the property was sold (the fact that it was let would suggest that you didn't) and that you didn't make an election for the first property to be treated as your main home for CGT purposes within two years of buying the second, you won't qualify for full main residence relief which your absence for work commitments would have given you. See the notes starting here
. However, all is not lost as you will see below.
If you made a £100,000 gain, it will be divided between tax free and taxable sums for each of you and your wife as follows::
Exempt gain £21,939 (£50,000 / 98 months x 43 months (25 + 18))
Non-exempt gain £28,061 (£50,000 / 98 months x 55 months (73 - 18))
Letting relief £21,939 (lesser of £40,000, £21,939 and £28,061)
Taxable gain £6,122 (£28,061 - £21,939)
Annual CGT exemption £11,000
Net taxable gain £0
Take a look at HS283 here
for information on the main residence and CGT.
I hope this helps but let me know if you have any further questions.