I have bought Rolls again, 1 off Rolls S12 27 (105Ah @ 20Hr) this time direct from Barden UK.

A major factor in choice is weight. I only want to lift around 30Kg. The previous HT 31 was 27.5Kg. The new S12 27 weighs 24.5 Kg, one size down from the HT/S12 31.

Details for S12 27

Rolls S12 27 – 12V Series 4000 Battery < £154: 3 Years Warranty
http://barden-uk.com/product/rolls-s12-27-12v-series-4000-battery/

Physical Specifications

Weight: 24.5 kg ~ 54lbs | Length 32.1 cm 12.63" | Width 17.1 cm 6.75" | Height Inc. Term. 23.8 cm 9.38"
Volts: 6 | BCI: Grp 27 | Cells: 6| Plates/Cell: ?
Terminal Type DT
Included Hardware S/S Hex Cap Screw, Nut, Lock & Flat Washer
Size & Thread 5/16″-18 x 1-1/2″

Electrical Specifications
Cold Crank Amps (CCA) 0°F / -17°C 660 Marine Crank Amps (MCA) 32°F / 0°C 825 Reserve Capacity (RC @ 25A) 185 Minutes Reserve Capacity (RC @ 75A) 53 Minutes

Charge Voltage Range
Bulk : Absorption = 2.45-2.5 V/cell @ 25°C (77°F) or 14.7v to 15v
Float Voltage = 2.25 V/cell @ 25°C (77°F) or 13.5v
Equalisation = 15.48 to 16.02 SG 1.280

Recommended Charge Current Capacity (String) 15A
Maximum Charge Current (String) 25 A
Self-Discharge Rate 5%-10% per month at 25°C (77°F)

Hour Rate Capacity : AMP Hour : Current / AMPs
@ 100 Hour Rate 140 AH 1.4 A |@ 20 Hour Rate 105 AH 5.25 A | @ 15 Hour Rate 99 AH 6.58 A
@ 10 Hour Rate 89 AH 8.93 A | @ 8 Hour Rate 87 AH 10.89 A | @ 5 Hour Rate 85AH 17.01 A | @ 1 Hour Rate 38 AH 37.8 A

Amphere hour capacity ratings based on specific gravity of 1.280.
Reduce capacities 5% for specific gravity of 1.265 and 10% for 1.250.