Hi Tony, I'm afraid I got lost following your computations below:-
As for Flat 3, I'm assuming that the disposal proceeds will be £48,480 (£151,500 x 32%) and that contracts will be exchanged in December 2013. The cost is £32,000 (£29,000 / 2 + £35,000 / 2). The gain will, therefore, be £16,480 and the ownership period to December 2013 will have been 116 months.
The gain for the period the property was your main home is exempt from CGT as is the gain for the last 36 months of ownership (excluding overlaps to avoid double counting). That accounts for £5,114 (£16,480 / 116 x 36). The remaining gain of £11,366 is split £9,519 to the letting period (less 6 months which are part of the final 36 months of ownership) and £1,847 to the vacant period.
As the property was both your main home and it was let you are entitled to letting relief which is the lesser of:
2 the sum of the main residence gain and the gain for the last 36 months of ownership of the property which is £5,114 and
3 the letting period gain of £9,519.
Letting relief will reduce the remaining gain from £11,366 to £6,252.
I understood the MRR of £5114, but didnt understand how you ended up with £6252. I got the letting period of 67 months;vacant 13 months & residential of 36months, but not how you arrived at £6252. It's late and probably brain not working right. Be in touch tomorrow afternoon.