ocean 47 battery removeal

[blue-max]

I have had a battery failure so need to change most of the batteries. All 5 of which 3 are large (50 cm x25 cm) are squeezed into the base of one side of the saloon seating. There is no space between the batteries and the timber base. I had thought I could remove the timber top but this one piece and glassed in. These can,t be original -boat is 15 years old so there must be a way to remove. My replacement batteries are same size.
Any help much appreciated

[blue-max]

For those reading my original post, I solved the problem by cutting open the top of the seating so I could lift the batteries straight out. To do that required removing cushion seat support - gentle fisting disconnected it -its fixed by steel pins! Also surprising was that the top was secured to the base by steel screws. These came out as did the angle brackets and 2 small cuts freed a section of the top to get the batteries out. Just needed a little supporting piece u nder one cut to put everything back securely